[robmog]

Doh! moment.I thought I had it all worked out but with all this assemble disassembly BS I got mixed up. Currently my S1 is 3.3 S2 is 3.1.
I have 3.0 3.1 3.2 3.3 and 3.4 shims available and those suckers are pricey!
I've established 6.4 is the correct total thickness. Should I try for the correct ratio where S2 > S1?
And how important is the 0.2 mm difference?
With my shims I can pair 3.0+3.4 and 3.1+3.3, I only have one 3.2 so unless I buy another that's out. I could buy the 0.25 shims to increase my options but that will take time. I had to wait two weeks for the 3.3 shim to come from Germany! They are not all available here.
Thanks to all for the advice.