How about a new set of handles from these guys
http://www.amresupply.com/category_view/P/PE,20,1


3. The valves are Waltec. The valve seats are fine. The installer
placed the assembly too far into the tile. The only way to turn the
water off is to keep the handle screw loose as the tile prevents the
tap from fully closing when the handle is tightly seated.
4. This causes the handle to strip out. Always.

Is there a way to replace or modify without the a completed tile job?