Dee - I sent you a PM... but in essence:
If your fins have a post hub as seen in the picture, they will work just dandy. Now, some fins (like my Quattro's) had a small ridge of plastic between the hub and the boot. It doesn't need to be there, so for the shackle to fit nice and secure behind the post, you need to file it away. A dremel will do the tool in about 3 seconds flat.
I use 11" springs. I have worn my XL Quattro's with size 12 DUI rock boots in this combo.... that's about the maximum I would recommend before going to a set of S hooks or something, just to add an extra inch on either side. If the spring is too large, the solution is even simpler. Take the aforementioned Dremel and cut an inch off, and bend a new loop in place using a couple turns of the spring. Bam - you're done.
As for two weeks, I'm in Canada, you're in Texas... likely, but it will be close. I normally charge $37 including the postage anywhere in North America... for FedEx Ground (delivery in 8 business days) to Texas, total cost would be $41.