Motul makes a nice semi-synthetic. I used it for all my bikes. Practiced rolling burnouts for 5 days straight. 18-20 tires later clutch is still solid.
Depending on how large the ridge you are making you may want to sand out the gelcoat and lay fiberglass. It's not too hard too work with. If you get an epoxy based resin you can add micro baloons that acts as a filler like resin for finishing work.
The only way to get Leduc's dimple dies are directly from his shop. He has 2 different sets. Of course the sizes you want are split into the 2 sets you have to decide which one will benefite you the most or just buy both sets but they are pricey. I think this is the number #951-845-8820. His...
Astro Pneumatics makes a really nice Iwata knock off. I've used one for a couple years now and its been great at less than 1/4 of the price of the Iwata comparable. I think Toolsparadise or spraygunworld.com maybe the same place has the best deals on em.
We use a 40 ton press. The metal starts to curl initially and you need the additional force to try and flatten the metal back out on heavier gauge material. Chromoly is a bit more stubborn than mild steel.
Dimple dies are a nice touch. We use them alot for the offroad application as it adds alot of rigidity. The ones I have found that work the best are made by Leduc. The JMR flares are a little flat. Here are a few I have on my car.
The bottom 2 pics are out of 11 ga.