Never, NEVER ASSUME any math done on the theory of lift is accurate with your parts, NEVER
To many ways for it to be wrong
If you don't have a set of decent checking springs get them now before checking any thing related to valve to piston clearances, use a good dial indicator on the retainers align exactly like the valve stem is and push it down to the piston starting around .030 BTDC every 5 degrees until around .050 ATDC on both valves.
I learned a lot on actual P to V clearances and rocker arm ratio theory checking them this way AKA this way is well worth doing
Make sure and check the max valve lift at the retainers with the lash set also so you can figure out EXACTLY what ratio your rocker arms are