G & G P90, mod to accept other mags

[Piers1989]

Hi there,

I'm looking at getting the G & G p90 and have read about adapting the gun to suit the other branded mags, something about the release catch being too short on the G&G.

Is it as simple as extending the clip under the mag a little with any solid and stick-able material?

Otherwise does anyone know if the upper reciever (the G&G comes with a green dot sight) can be replaced with a standard tri rail, like this one? 

https://www.evike.com/products/30711/

Also considering the simple mount base mod:

https://www.amazon.com/F-FACTORY-Tactical-Mount-japan-LAYLAX/dp/B000XQ6CCG#customerReviews

Thanks