I brewed this recipe back in August and it is tasting very good now. My efficiency was way low so I had to add some dark DME and table sugar in secondary to attempt to reach my target abv. In the end, my abv is at or just below 10% (~9.95%). I let this sit in primary for about 1 month, transfered to secondary for about a month, and then bottled. I rehydrated some dry yeast (I didn't record which yeast I used) and added to the bottling bucket at bottling time to ensure adequate carbonation. I added corn sugar to about 2.3 vols of CO2.
I wasn't thrilled with this beer after about 1 month of bottle conditioning. It was not well carbonated at this time and tasted a bit off. After about two months in the bottle, carbonation and overall flavor significantly improved. A couple of weeks ago I tasted my version next to the Ten Fidy and preferred mine because it had a bit more carbonation, was slightly sweeter, and seemed a bit less thick on the tongue (I finished at a SG of 1.027 but the increased carbonation of mine also likely effected mouth feel). My wife tasted mine next to the Ten Fidy blind, not knowing which was which, and preferred mine also. Her comment was that mine was better carbonated, more flavorful, and slightly less thick and syrupy.
Overall, I'm very pleased with this recipe and would certainly recommend it. My wife and I have tasted it next to other imperial stouts, like Bell's Expedition Stout, and have consistently preferred mine (all of her tastings were blind). With this batch I bottled about 3 gallons as it was, put 1 gallon on oak chips & bourbon, and 1 gallon with 50 mL of Still Spirits Top Shelf Chocolate Cream Liquer Essence. I'm pleased with the results of all so far. I also took the same base recipe and bumped it up to make a 3 gallon batch of 14.4% imperial stout. I added some liquid chocolate extract to all 3 gallons, and some raspberry extract to 1 gallon for a raspberry chocolate imperial stout. I just bottled this big one last week so it will need to sit for a while before tasting.
The only thing I would change when I brew this again would be to mash with less water and sparge with more. I think I sparged with 1 gallon of water, which is nothing on such a big grain bill. Hopefully, this would improve my efficiency.