Use mrmalty.com to see how much slurry you need. The slurry should be yeast, and not trub and yeast. You can look up how to rinse the yeast. Or you can just use the cake, this works, but a clean slurry is even better.
Barleywines do not have to take a year to be mature and ready to drink. Here are some key items. Propper amount of yeast (you know this already), give the yeast plenty of O2. Control the fermentation temperature, as these can take off like a rocket and generate a high temperature and the fusel alcohols that go with it, and then you have to age for a year. This is the way I have made a pretty good Barleywine that was winning awards at 3 months.
Sierra Nevada makes Bigfoot after they are done with Celebration Ale brewing, which is made right after the hop harvest. So the make Celebration in late Sept/Oct and then brew Bigfoot, which is released in January. Not too long.