if it helps with your project:

Godzilla vs mecha godzilla (1970s)

Terror of Mechagodzilla

and Godzilla vs megalon

all have the same english dub so do not bother with those

the media blasters DAM disc as mentioned has the aip dub, but a nice fan disc that was organized a number of years back via newsgroups had a sound editor using various tv broadcast and such to reconstruct and clean the aip dub. This was then made to fit the then ADV destroy all monsters disc.

I took it a step further and then made that audio fit the fareast flix destroy all monsters disc. They ripped the region 2 dvds and then added in removable english subtitles. I then added in the aip dub to that

Also most seem to forget that the DAM AIP version actually had a short end credit sequence. I have been meaning to up that to youtube since I recorded DAM off the tv twice back in the 80's and between the two could get the complete sequence