The difficulty will depend on if you are starting with a slide swimmer or silent killer.
The slide swimmers are already a SS bait, the SK is a floater but there are a few things you need to do:
With a SS, you can remove the front hook and split ring. Insert a flat screwdriver or something similar from the joint up to the hook hanger to assist in lifting the skin up over the hanger. The front skin pulls forward, over the nose. You'll then see the cavities with the weight in them. You can add or remove weight at that point, reinstall the skin and hardware and test.
With a SK, you'll still remove the hook and ring from the front but you'll also have to cut the bill off and sand it down to where you can slide the skin off the front. I've converted quite a few 250s this way and it works fine, it just takes a steady hand so you don't mess the skin up with whatever you're cutting the bill. You'd then follow the same steps as above with removing the skin but you'll definitely need to add weight as there is none in the body cavity of a SK. I prefer tungsten putty but they sell Deps tuning weights specifically for this application. An additional step with a SK is there is a weight in the tail. You'll see a drain hold on the bottom of the tail. I usually take and Exacto and make a small incision, use forceps to grab the weight and then slide it out the bottom.
The difficulty is also going to be different if you are working on the OG (foam) or the new style (injected).
I don't mess with the back section skin as it is glued/epoxied to the bait. The front section has no adhesive on it.
Hope I covered it enough. Feel free to ask, I'm far from an expert but I've done it enough to know how not to mess it up.
