Flexplate is not fits the torque converter

Bobzilla said

10237 is NOT equal to 10242.
BMM 10230-MAGBAL is a B&M 10230 the Hughes cuts to match the discontinued 10242. They cut the proper size and shape notch into the 10242.
For reference, I will add a photo of the 10236 LA 360 balance on top of a 10242 Magnum 5.9 liter balance.
It is normal for the cutout on the B&M flex plate to be opposite location of the factory Magnum flex plate weight. That makes the side with NO cutout heavier to match the position of the weight.
View attachment 1715594379

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So how I see it - flexplates:
1. 10236 (for 360 LA) have the biggest cut
2. BMM 10230-MAGBAL or 10242 is for Magnum and it's have a bit smaller cut
3. 10237 is have even smaller cut than 10242, so needed to be "adjusted"
4. All mentioned flexplates above have the similar bolt pattern.

What I have to do is to cut from my 10237 a bit more to get closer to 10242 in term of weight offset? How much should I cut? in mm? maybe there a chance to get a template? how to cut not too much and not too less?