If the pistons just need a solvent cleaning use regular old O'Reilly's brake clean. Don't use carb clean, it leaves a residue that might eventually react with the rubber parts. Actually, xoap and water would be just fine, as long as the pistons are completely dry before reassembly. If there are tougher rubber deposits on the pistons I just sashay over to the bench grinder and polish them on the wire wheel. Follow with the solvent/cleaning metod of your choice.
I was never sure of what the red stuff was for, many Japanese OEs include it and/or another packet of a different color lube. Personally I always just wet my fingers with a little brake fluid and then pull the o-ring through them. Place it in it's groove and then insert the rubber boot into its groove in the caliper (I can't recall if the SVX uses an internal or external boot. I'm figuring if you're asking it must be an internal. The externals have a steel ring to hold the boot on the outside of a lip. The internals usually just sit in place in a groove and the piston eventually keeps it in place. Some internals have a larger groove and a steel ring. Whew.
) The internals without a ring are the more difficult to install. If you have clean, dry compressed air available you can blow air into the caliper therough the brake hose hole while pushing the piston into the boot. When the piston touches the boot it balloons out and over the piston. In the absence of compressed air you will give your dexterity a workout. After placing the boot into its groove place one finger from each hand inside the boot and use your thumbs to slide the piston down those fingers while they gently stretch the boot over the piston. Once you do it you'll see how easy it is, but be prepared to spend a few minutes doing the first one.
If the boot is external just place it into position over the piston and insert the piston into the bore. Position the boot as required and finish it off by installing the steel ring.
Use a good disc brake silicone grease (a good thing to have around for many items) to lube up the sliding rubber parts and you're home-free.