Don't waste your money! The std slosh runs perfect on blocks. The spools are lightweight and the reels are very docile. I don't use them anymore (use f/spool) but one red block in a 30 or one white in the 20 should be all you need. Play about with line level and if all else fails you need casting lessons.
Ceramics won't make any difference either and may spoil the reel. Stick to heavier oil as well there is nothing to be gained from running them superfast, unless you like unpicking birds nests!
Never used white spirit, lighter fluid is what I would use. Make sure you clean the pinion and spindle, add a smear of oil and a dab of thick oil to bearings. Dont forget to clean the spool edges and inside the frame. The tolerances are quite tight and crud can build up causing drag.
line level is the most important thing to get right on sloshes.
Would stick to lighter fuel m8,never heard of anyone using white spirit,just soak in petrol(lighter fuel)for a few mins then dry/air out on paper toweling,then add a drop or two of your chosen oil(not to thin).Got a 20 n a 30 myself,cast pretty well imo,n don't do bad in the ruff stuff either.Got to agree with chukka,just keep e'm clean n a bit of lube n they will stand u in good stead.Regards magging,wouldn't bother m8,I know a few lads have done n r happy, some others found they had spool wobble/noise because of the glued on metal disc,the shv's don't need the mod has they have the metal spool fitted.Good reels imo tried n tested..
Other spools on different reels aren't magnetic either budFirst thing you need to do is put a metal disk on the spool as the spool is not magnetic, then with the extra weigjt to one side of the spool un balances the spool causing it to be noisy and vibrate plus a badly un balanced spools will damage the bearings.