How high you drill your hole in the bucket depends on the size and shape of the spigot.
Some spigots have long downspouts (to facilitate transfer hose attachment).
You have to factor that length into the height of the hole.
I've had some plastic spigots with downspouts that were practically flush with the bottom of the bucket.
If one is not careful lifting the bucket and setting it down, then a lot of weight and stress can be placed on the spigot and can result in a catastrophic crack or rupture and loss of beer (and a really big mess to clean up). This is really easy to do when plastic is cold--it tends to crack rather than give/bend. I've cracked a bulkhead and had a leaky spigot until I figured out why it happened.
If the hole has already been drilled, and the spigot downspout is flush with (or extends beyond) the bucket bottom, then just re-orient the spigot at a 45 degree angle. It'll still work fine. Some spigots have a vent hole (through which O2 can enter the beer during transfer). If yours has one, I'd use a sanitized PVC glove + thumb to cover the hole during transfers.
Don't try to go as low as you can--you want some dead space in the bottom for yeast and trub collection.
To minimize waste and get the last little bit of beer (and often the topmost layer of yeast--good if you're harvesting), you can always tip the bucket towards the spigot as you're finishing up.
I personally would not try the grommet and hose idea.