Technical Flathead Block Relief Advice

Hello all,
I have read the fantastic 2011 "Flathead Block Relieving for High Performance Flow - How To" post from Bored&Stroked, and I'd suggest it to anyone about to tackle the job of relieving their Flathead Ford for the first time. I didn't want to hijack that thread but...

I am about to jump in on mine using the router and die grinder method. I'm looking for a little advice on how deep I can safely go with my 4.25 stroker build. I've read everything from 0.085 to 0.1875, and I can't exactly put it all together and measure it because the final machine work hasn't been completed, and the rotating ***embly is off being balanced. From what I can figure, a .125 relief cut will leave me with a decent compression ratio, but I don't know if that's safe with the 4.25 stroke. Disclaimer: I can turn a wrench, have a tool & die background, and have tinkered with flatheads for a few years, but I am not a professional, just a guy trying to learn as much as I can as I go.

My engine specs are:

59A block, bored 3.312, intake and exhaust ported, (also manga fluxed, thoroughly cleaned and de-rusted, sonic checked cylinder walls, new valve seats)
4.250 stroke Eagle Crank
7" **** Rods
3.312 Ross Pistons (80576)
Offenhauser 425 heads
1.6" oversized Manley ProFlo intake valves
1.5" Manley ProFlo exhaust valves
3x2 intake with Stromberg 97 Primary and dual Stromberg 88 secondaries
New adjustable lifters, springs, oil, and water pumps, etc
TBD Schneider cam regrind with all specs and use case in mind

Just for added info, I had major cylinder wall damage from a loose wrist pin, and then a rear main bearing failure, which kicked off this rebuild for my full fendered steel 1933 Tudor. The intent of this build is to be able to run the car in New England vintage drags, and hit the road even if the tune isn't ideal for the street. I'm hoping the significantly increased displacement will make up for some of the low-end torque that may be lost. I am currently running the OEM 3-speed and banjo rear, but I have a T-5 for it and will upgrade the rear end eventually.

Any advice on my depth of cut before I start irreparably altering this 80-year-old hunk of cast iron would be greatly appreciated!

Respectfully,
Cody