I just made this decision recently:
I took the rails off and sold them for like 50 bucks profit.
Bought 1 sheet of hydro turf, around 50 bucks.
Bought a small can of contact cement, 6 bucks at walmart
A throw away brush 1 buck a walmart
a three inch block of foam from ebay, 15 bucks
lifters (foam blocks) 15 bucks
under pad foam layer 15 bucks
If was my first time doing it, and my thought process was to do the front up for a permanent job, and then leave the back open to do different foam block location jobs until i figure out what i like: lifters work well, degree of kick plates, distance, ect.
I learned a lot and made plenty of mistakes going through it. Here's my tips on doing it: Get the thickest under pad foam layer (like the 3/4 inch thick one!) and get the (1cm) thick one for your walls if you plan on leaning on them to carve buoys. Make tensile-trace outs out of plastic or cardboard(for the flat areas) and then take them over to your hyrdo sheet to cut out (be cautious of the pattern direction). Make your cut's conscious of the blade direction to create seems that will match. You can use a heat gun and get the hydro turf to mold to your ski shapes a little bit before you glue. If you do the gluing right though, you can just push the turf down and it'll stay. Apply glue to both sides, sometimes an extra layer to the foam side because it'll absorb everything.-let em air out, and when you touch the surfaces and it's really tacky. They are ready to be combined. Start from the bottom edge because once they touch, they arn't moving! Then get a hammer and a wood block, and beat down every section after you combine them. Also, it doesn't hurt to have excess edges to trim up with an exact-o blade when your done... but most of my job came out better if i just got it measured right the first time and heat/molded it on there to check.
Final advice: don't do it. keep your rails, buy the pre-made bottom piece, keep your front panel(and silicon the crap out of the holes it screws into at the bottom-water tight) It'll cost you less, take less time, and the end result has a higher chance of being good looking and function. BUT HEY.....whatever!