Weyermann Rye Malt 1 lbs, 4 oz
This type of malt needs to be mashed, and might even need a protein rest. If you're steeping, you might have problems with haze and/or storage stability. It will definitely do great things for head formation and retention, however!
Centennial Pellets 3 oz @ 60 mins
Centennial Pellets 2 oz @ 30 mins
Cascade Pellets 2 oz @ 15 mins
That's a whole lotta hops. Definitely going for the American interpretation of the style. More to the point, all that hop bitter and citrusy hop flavor might very well clash with your dark malts. It's tricky to make a good hoppy dark beer, especially if it's big.
Oak Chips, Untoasted 1 ea
Don't need these, at least not yet. Let the beer ferment and condition, then decide if you want to oak it.
White Labs Super High Gravity Ale
This might be OK to finish off, but at lower OG you might want an ale yeast which throws more esters to help accentuate the sweet, chocolate notes. In any case, you'll need a big starter and lots of oxygen/aeration to keep your yeasties happy. You might also need to start off with a lower OG and "feed" the fermentation over a period of weeks by adding fresh wort or DME.
OG 1.134 FG 1.027 IBU 67.9 SRM 60.51 ABV 14.02
Not to discourage your experiments in rocket fuel production, but making a beer much above 10% is tricky and such beers can take years to come into peak condition. When young, they can be really hot, harsh and solventy tasting. Reduce your grist bill by 25% and you'll get a nice, authoritative RIS that's ready to drink in just a few weeks.
I know dark extract isn't popular on this forum, but hopefully someone can 'splain me better why. Which extracts should I use, how should I modify the specialty grains, should I use different grains, etc?
Garc_mall basically got it right. You don't know what the dark stuff in the dark extract is. It could be relatively flavorless Sinamar or caramel color or it could be roast barley. Better to just use LME to substitute for base malt and steep your own dark grains for color and specialty malt character. It gives you better control over flavor, aroma and color.
Also, I am assuming I would need at least a 6.5 gallon bucket with a blowoff tube, but would you recommend something different? How do you handle beers like this that will have a lot of krausen? Having an exploding bucket is definitely NOT an option!
Big bucket with blow-off. Or split the batch into two different carboys/buckets. In either case, for primary fermentation you want a lot of head space. This is a style which produces a lot of krausen fast and there's lots of crud which can clog airlocks and blowoff tubes. My first attempt at a RIS got the name "Chernobyl #3" for exactly this reason!
Primary and secondary fermentations - how would you approach these?
Start off with a big starter (at least 1 quart, or perhaps 2 smack packs or dry yeast sachets) of American Ale or English Ale yeast. Aerate the hell out of it - probably 30 seconds worth of oxygen through a sintered airstone. Start fermentation on the cool side of the yeast's preferred temperature range, letting temperature rise by a couple of degrees once O.G. drops by at least 50% and krausen drops. Finish up on the warm side of the temperature range as gravity drops to desired F.G. The idea is that you're trying to limit production of esters, aldehydes, fusel alcohols and other fermentation byproducts.
For a really big beer, you might need to rack the beer, add a different strain of yeast and/or feed the fermentation to get desired ABV. This can take weeks.
Condition at least two weeks at cellar temperatures (~65 *F), perhaps cold condition for another 2-3 weeks at 32-55 *F to clarify and smooth out the flavor a bit. If necessary, rack and let it condition even longer, either at cellar or refrigerator temperatures.
Bottling and conditioning - what's the recommendation as to how to approach this? Besides the obvious effects of aging, what considerations should I think about when it comes to aging a beer like this in bottles?
Make sure that you've really hit terminal gravity. There's a lot for yeasts to eat in a Russian Imperial Stout, so you don't want to bottle too soon - unless you like homebrew hand grenades.
If you had to cold condition or condition for an extended period of time, you might need to add a bit of new yeast at bottling along with the priming sugar. Due to the high ABV, it will take the yeast a long time to produce the proper levels of CO2.
If you have the technology, it might just be simpler to keg, force carbonate and bottle using a beer gun.
For long term storage, keep your beer as cold as possible without freezing it. Also, work to exclude oxygen from your beer at every stage of the production and packaging process. Blanket conditioning buckets with CO2, don't splash wort or raw beer. Get a good seal on your bottle caps and use oxygen-barrier caps. Dip the caps in wax to further exclude oxygen.
Can I just use less extract?
That's the easiest way to do it. Basically, use extract like you would use base malts if you're an all-grain brewer - for the bulk of the fermentables, but not so much for flavor and aroma.
I also want to assure maximum body and color. I'd hate to brew an imperial stout with an ABV > 10 that wasn't thick and chewy, or didn't come out of the bottle looking like used diesel oil. However, the target of 60.51 SRM on the sample recipe... how does that compare with your RIS recipes?
60 SRM is a bit on the light side. Adjust color using Carafa malt (basically, dehusked patent malt) or if you like your coffee and burnt grain character, add a bit (like no more than 1 oz.) of patent malt and/or roast barley. A little bit of the dark stuff goes a long, long way.
BTW there is no chance of my attempting to brew this one anytime soon, I have five or six others in the queue before this one could be attempted.
Get this one done soon, especially if you don't have great control over fermentation temperature. Big ales fermented during the summer can get way too warm and produce solventy, phenolic and excessively estery notes. If you're in a part of the world where it's already warm, you'll have to put it off until it gets cold again or use some method of cooling.