Wet sanding TO & small amount of Turps added should be done with 1200 or 1500 grit Wet & Dry paper as 600 or 800 have too much bite and will strip off more than what you bargain for. Even 1200 can strip the best part of 3 coats off.

Would recommend this twice or maybe 3 times only up until about 20 coats down and then switch to proper wet sanding every 2nd or 3rd coats using water with a drop of dishwashing detergent added as the lubricant. 1500 & 2000 grits work best the nearer you get to 30+ coats down.

Cheers, Waz