I tie uni to uni any time I fish braid with a fluoro leader, which is any time I'm fishing a shakey head, wacky rig, or small jigs. That being said, you're using WAY heavier braid than I ever would. 12 lb braid and 10 lb fluoro has been a nice balance for me. I'd be very concerned about knot failure with the massive difference in break strength between 10 lb fluoro and the heavy braid you're talking about. Probably worth mentioning that I only fish braid/fluoro leader on spinning setups.
That being said, I've never experienced a knot failure when following these rules of thumb: 16-18 wraps on the braid side, 8-9 wraps on the fluoro side. Think of the braid end as the stopper, don't get cheap on wraps. Take your time and wet the knot as you cinch it, making sure it doesn't get bunched up.
I like to use hi vis braid with around 6' of fluoro leader. This will help you with bite detection, and allow for a few break offs without having to tie a new leader while on the water. If you do a good job with your knot it should cast right through the guides.
Good luck!