Might be worth a try - the top of the twist where the friction starts being applied to the single mainline stays a bit looser & allows a bit more movement perhaps ?

I spent a lot of time testing knots on a line tester and I can tie a pretty good uniknot. Possibly the simplest knot is the clinch knot yet I suck at that and got poor results on the line tester. Yet I did really well with the uni knot. seems too silly to be true but it is

 

Nice and easy

The bimini loop is either used to loop/ cats paw a swivel/ clip whatever or similar on the end.

 Or use the looped end as a double strand for a knot to tie the leader to  eg albright/ yucatan/ blood...

Is the latter what you guys are doing and failing?

Doing this increases the size of the knot and how it goes out the eyes on a cast.

I have never had a bimini fail, used as a loop knot.

 The most common reason for fail of a knot is where there is a point in the knot thats is under tension one line crosses at a sort of 90 degree, that causes the crossed section to be 'cut'

  eg albright at the end that the doubled line goes over the tag ends on the line on the outside.

Ok so I have tried a bunch more with varying degrees of success all however have still broken at the top of the twist. Number of turns hasn't seemed to make a difference 25 and 50 turns both broke near enough the same pressure. 

The picture below is of 2 twists tied in Shimano Ocea EX8 PE8 braid and 2 twists tied in Tasline Elite white Hollow PE8.  If someone can see something obviously wrong with how I have tied any of them please let me know. 

I tie mine of the end of the rod using the rod and drag for tension.

 Very quick to tie.

wrap braid around little finger to hold tension... 

 Foot on trace to hold tension.

 Wind the trace figer of 8 motion around the braid  keeping tension of everything.

 VERY VERY important to pull up  after no more than 8 figer of 8s

Also very important to pull up each finish before proceeding to the next...

 Pulling up on a knot in briad is a must.

Bimmini breaking at the top....had that with some cheap yellow stuff was given few yrs back.. it went little fluffy after use.

Again bimmini is a quick knot using the rod as 3rd hand to keep tension.

I use it in end of braid line to loop a swivel/ clip on the end..

Take braid off the end of the rod, double back with a good tag end.

2 fingers in the bottom of the loop, and hold top with good length tag loose keeping tension on the braid.. twist up around 30 times...always hold tension... put little more tension on, hold end of tag and bring down towards the fingers holding the end of the loop... the tag twists tight around the twists. Finish with 1/2 hitch each side of the loop.. holding tension and pulling each up as you do them...3 or 4 to finish around both sides of the loop.

I did have issues early on with 'lassoing' the swivel into end of the loop breaking there.... now pass thru 3 or 4 times in a cats paw... these cant be pulled up each time pulled thru.. found any more than 4 they will not pull up well sometimes.

I think the failure at the top of the bimmini will be either the type of braid or not holding tension all the way thru tieing, or a little of both.

https://www.youtube.com/watch?v=pjzUb5QRKuk

And the biggest mistake they see people make:

https://www.youtube.com/watch?v=LD1gWbp9zKo&t=15s

I used to use Nathan from Big Angry Fish's method, but sometimes didn't get it right with that - because it's easy to not tension correctly when you just flip the braid over the mono loosely, then try to tension everything up.

the method above is based on wrapping the mono/fluoro over the braid under tension, and it seems to work better for me. I've done it in the boat, and on a wharf, successfully using this method.