[clinebarger]

You may have a harsh Reverse engagement using a wave plate in lieu of a Belleville, Especially if your R/I Drum & Pump Stator both have large feed holes....It can get nasty!

Use 7 High Energy Frictions & 6 .077" Steels along with GM# 8685044 Apply Plate & GM# 24212460 Backing Plate. The extra friction will help handle the torque.
The Apply & Backing plate are the latest 4L60E designs & are really stiff to reduce flexing.

The 2nd Accumulator springs in the Younger kit work very well to smooth out the 1-2 shift, Drill the 2nd feed hole .076"-.086". Watch your Band clearance! I like about .060".

With the low rpm torque your going to produce, A .500" TV Boost Valve would be a good idea, Sonnax# 700R4-LB1....Use the supplied PR Spring in place of the Green TG PR Spring.

Pump Rings & a Higher Rate Primer Spring is also recommended Trans-Go# 700-PHK.

I'm not here to roast anyone, The best I can do is advice! While what you did is unconventional & I have a serious concern that Solder would flow into a feed hole & restrict it, That air testing will not detect....I hope it works out for you!

What I do in a situation like this.... I buy a New 300mm 4L60E Input Drum from GM ($175) Press the 300mm shaft out, Press the 298mm shaft in with retaining compound.