273 Rockers on a 360

So...here's a little more info.
I've ready Mike's site at B3 and it's great information.
Stock pushrods definitely won't work in my situation....I would have no threads showing on the adjuster. In fact, it wouldn't thread all the way through.
I've considered clearancing the pushrod guide hole with a carbide bit, but believe I need to make sure the geometry is correct on the rocker arm first. All of the sweep data I have seen with rockers has to do with roller rockers. Is it the same information for the 273s?

If the correct sweep for a 273 rocker is closer to the middle, rather than what I have now, then the solution would be to shim the rocker shaft to make them higher on the posts. I've seen the concerns about splitting the towers, but that can be avoided with trimming the shims or getting tapered shims. The only shims I've seen are the non-tapered. Has anyone ordered tapered shims somewhere?

I've got lots to learn....thanks again!

PS....I will take some more pictures tonight to explain how a standard length pushrod would fit.