Long-time lurker, first-time poster. I brewed an extract Belgian dark strong at the end of July. 11 lbs of pilsen and wheat extract, 3 lbs candi syrup, 2 lbs turbinado. I added the simpler sugars incrementally after high krausen with Wyeast 3787. The virtual OG that I came up with was 1.100, and after a month in primary, the yeast got it down to 1.016 (83% attenuation). It's been standing pat for the past 3 days at that FG, so I'm pretty sure it's done. I'm completely OK with it being done where it is, I'm just concerned that the yeast have given up and there's still sugar left to be consumed. I've gotten 87% attenuation out of 3787 before, so I know it can do better, but that wasn't with nearly the OG burden that this brew had.
My question is whether or not it's safe to move to secondary for conditioning and eventual bottling, or if I'm running the risk of bottle bombs down the line. I was going to pitch more yeast at bottling since 11% ABV and months of aging can take its toll on the original population, so what if there are some more fermentables that were left untouched? Do I prime with less sugar? Do I try and get it down further by rousing? I already upped the temp to 78 to get it to finish, so I doubt I can do much more then. And like I said, it just seems "done." The gravity sample tasted surprisingly good; a touch on the sweet-side, but nowhere near the harsh or hot alcohol flavors I expected. My biggest concern is the potential for my basement to get decorated with broken glass and foamy brown goodness. Thanks in advance for the input.