Angel is the first press. Odeon is the second press. Angel is the more sought after and will command a higher price
Frend2001, I am not sure what is the co relation between the wt of the vinyl and its sound quality. Maybe other experts can chime in. Also as thickness of vinyl changes, one needs to change the VTA on the tonearm. This is a feature that most tables dont have.
I find the pre 1985 EMI/HMV lps to sound very good. Absolutely no issues.
Souravin, the golden Odeon sticker in the later releases was put for business reasons. Odeon was the releasing label for the international market. So unlike in the 60s when there were separate presses for Angel and Odeon, post 70s, they just affixed the Odeon label on the Indian release and shipped it abroad.