Suppose a 95 or 96 magazine spring may work, but may need some alteration.
As to your floorplate, I'd rig something using my benchvise to try to straighten it with out removing it.
As to the Williams peep sight. Had one on a 91 Argentine I bought back in the late 60s. Think todays Williams is still the same one. Its OK. Only negative thing about it to me was it had no knobs to turn to adjust elevation/windage.....used a small screwdriver to make adjustments.
