63 Valiant - rust in front A-arm mounts

All, got all the front suspension off, and cleaning up, in preparation of new front end and disk brakes from DrDiff. Found some rust in the upper A-arm mount (driver's side, don't know passenger, yet). Wanted suggestions on repairing...I'm hoping I can just 'sister' an L-shaped piece over it, maybe a gusset, without having to tear it farther down. I want it safe, but it's a stock 170, we're an

PXL_20230507_004136974.jpgoldish couple wanting to enjoy a convertible, so not like I'm putting in a 340 and takin chicanes at 70...

For orientation, this is the front mounting point for the upper A arm, driver's side.

As always, thanks for the help!PXL_20230507_004207177.jpg