How many feet of chain on the line? Sometimes a couple of feet can make the difference
From 2014 to 2016 I used a cheap, perhaps Yamaha original, danforth anchor in Bimini with 5' of 5/16" chain connected to an anchor buddy and 100' of rode attached and 200' of additional rode in a bag.
For 2017 I upgraded to a Fortress FX-7 leaving everything else the same.
I also borrowed a Mantus anchor to anchor a friend's boat in 2017. And I always take a coated river anchor with 5' of 5/16" chain as a stern anchor.
I owned a very nice box anchor for several years. I never took it to Bimini. I would not want to bounce that hunk of steel across the Gulf Stream. I used it once in the years I owned it. I sold it to a friend who returned it to Texas where everything is bigger.
So my experience is this.
1. River anchors are useless in Bimini. They will slow the movement of the stern. They will not hold the boat in place.
2. Cheap Danforths will work in most conditions. It may set on the first attempt. Just drop it, don't throw it.
3. A Fortress FX-7 fits in the anchor locker and will not damage it. It may set on the first attempt. Again, just drop it, don't throw it. In heavy waves our FX-7 held two boats when the well set river anchor would not hold one.
4. A Mantus may fit in the anchor locker. It is heavier and less convenient than a Danforth. It may set faster than a Danforth. In my one experience setting one while standing in the water it worked well.
5. An anchor buddy (elastic anchor line) will reduce the shock on any anchor greatly increasing its ability to hold. Buy one. It is well worth the $40 on the lake or in the ocean. I believe ours is has four summers of use and still works like new.
I have seen all kinds of anchors fail to hold on windy days at the Sapona. More scope may be the key to holding in those windy conditions. The best solutions I have found there are to snag the mooring ball if it is available or tie an achor line to the Sapona. If it is windy and the Sapona is busy it is best to find somewhere else to enjoy your time as many boats will be experimenting with their anchors.
If I buy another anchor for Bimini it would be to replace the stern anchor with a larger Fortress or possibly a Mantus anchor. The additional weight of the Mantus might make it more useful on a lake to hold the stern in place but at several times the cost of the river anchor I am not sure how I would feel about using it that way. A larger Fortress would store flat and be excellent for windy conditions or to help a friend anchor.