Originally Posted by slob

1. the depth is a bit variable, it may be 2-3mm more now but hydraulic systems self adjust to some degree (like pumping your brake pads onto the disc after the pistons have been pushed back into the caliper). I you remove the reservoir cover on the master cylinder, how far canyou push the piston back into the slave? 7-8mm? Then a 10mm spacer would fit. Keep an eye on the reservoir, you might need to remove some fluid!

2. ~1mm sounds right, from looking at the top plate on a dry clutch with an open cover.