The bimini top works better for me, mostly because I like to look over the windshield when I am at the helm. The convertible is great for use in cold or wet weather though. I have mine for sale if somebody needs one: http://maxumownersclub.com/forum/viewtopic.php?t=510
I don't think trying to change your top to a bimimi would be worth the cost or the work involved. I purchased my 6ft sunbrella bimini top with double wall aluminum poles and mounting hardware for $200 a few years ago from GMI. I am sure that the price has risen, but I bet the cost of the fabric, poles and hardware would be almost as much if purchased separately.