I haven't had a spool up front, but have kept my selectable locker engaged to see what it would do. Does steer, but is very slow to steer. It binds up pretty hard in the corners. A set of good axles are a MUST. That said, I'd never run a front spool. I'm running an OX locker. I ever break it, it will for sure be my own fault...
That said, my driving style is pretty conservative, given the cost of parts and that I am usually racing and try to finish well. Even when just crawling/trail running I try not to push the limits of my equipment.
Edit- if you are running an open diff right now and just want to try it, go for it. Just weld the spiders up and roll with it. You won't be out a whole lot (other than spider gears and an open carrier). If running stock shafts, expect bad things. I'd run with 1 hub unlocked until you need it engaged.