Tieing a Bimini with braid can be a bit of a pain because the line is so limp, that's why I like to double it up. Just keep tension on it as you slide it down and it will turn out nice.
i would use the uniknot. i use braid on ALL my spinning tackle from freshwater 14lb test all the way to 80lb superbraid. the uniknot is what i use to attch them together, havent had any problems yet and ive been using braid for 3years now.
you could also try the noname knot for your braid to mono connection. one thing i always heard to do was to super glue the knot. this will stiop the braid from continuing to pull tight until it cuts the mono.
I know this may be sacreligious to some, but IMO the easiet, strongest, and least hassle is to simply use a Spro.
If you insist on a knot, I like the double uni on the braid to uni if the Flouro is less than say 60lb. If any heavier, the knot on the flouro end gets pretty big and I would recomend a no name. But you have to be very careful geting the flouro to "grab" the slick braid. Once you do, I dare you to be able to break the sombich.
UNI TO UNI WORKS GREAT, BUT I ALWAYS DO A BIMINI WITH THE BRAID TO DOUBLE UP THE LINE. I USE 15-18 TWISTS. THEN MAKE SURE THAT THE UNI WITH THE BRAID HAS AT LEAST 8 WRAPS(MORE WITH SMALLER DIA) AND 4 WITH THE MONO. THIS KEEPS BOTH SIDES OF THE KNOT CLOSER TO THE SAME SIZE.
IF THE MONO IS MUCH LARGER IN DIAMATER, I WILL USE THE ALBRIGHT/BRISTOL WRAPPING THE DOUBLE LINE BRAID AROUND THE MONO AND AGAIN USING MORE WRAPS THAN I WOULD TRADITIONALLY WOULD WITH MONO (10+) MORE WITH SMALLER DIAMATER BRAID(<60#). JUST BE CAREFULLY WHEN PULLING THE LINE TIGHT SO THAT THERE ARE NO SLACK SPOTS IN THE NOT WITH THE BRAID. HAVE NOT HAD ONE FAIL SO FAR.
CASEY
P.S. I USE THE BIMI WITH ALL TERMINAL KNOTS ON THE BRAID EVEN WHEN PULLING THE PLANNER. AFTER READING THAT ARTICLE IN SALWATER SPORTSMAN, I HAVE GONE FROM DOING 25-40 WRAPS ON THE BIMI TO LESS THAN 20 BASED ON THEIR STUDY. I HAVE NOT HAD ONE BREAK TO DATE.