Getting close to finishing a 48* Ritter W9 build and trying to get past the last hurdle, pushrod clearance. The W9's are CNC ported to the max and I'm having a problem getting clearance for the 3/8 intake pushrods with the 1.65 Jesel rockers. I ground enough to fit 5/16 pushrods with 0.010 clearance and the intake port wall is 0.060 to 0.070 thick in the relief area. What's the minimum safe intake wall thickness?

Whatever won't crack !!

For that, if you are getting that close on clearance, I’d use at least a sing tapered pushrod. 5/16 on the top and 3/8 on the bottom. Depending on lifters used and such, you can run a double taper.

sounds to me like your intake rocker does not have the right offset.

Higher ratio rockers are almost always* made by simply shortening the pushrod side lever.
Lengthening the valve lever moves the tip off the stem center*.
Example: a 1.5:1 rocker 1.40" long (tip to adjuster) has levers .560" and .840" long. To get 1.65:1, the short lever is reduced by ,051" to .509". The pushrod is now .051" closer to the near edge of the clearance hole.

* unless the shafts are relocated, which explains why very high ratios are very $$$