How important is temp control for secondary fermentation. I've got a barleywine that I'm planning on doing a long secondary on apple brandy soaked oak cubes with, and I have limited fermentation chamber space.
Temperature for secondary/long term aging is less important than primary fermentation temperature. Cellar temperature (~55F or so) is best, but it will be fine warmer. Higher temperature increases the rate of flavor development, for better or worse.