Bass Amp steel chassis gauge question

[Sethyrish]

Hi.
I need some advice on amp chassis steel gauge as the last amp I made needed an extra sheet of aluminium to support the weight of the transformers.
It seems most people use 16 gauge 1.6mm steel plate but this is a bass guitar amp with 16 to 17 kg, 35 to 37 pounds of transformers, on an 18 x 9 x 3 chassis. The next gauge available to me is 14, 2mm.
I plan on getting it laser cut and have drawn it up in Adobe Illustrator and converted to DWG file, as the price seems reasonable these days. I’m guessing I’ll have to find someone to bend it as well.
Another point is that it doesn’t seem any more expensive for stainless steel.

Would 16 gauge support 37 pound or go to 14 gauge?
Is it worth going stainless?

With a octal socket, where it the tube writing in relation to key, so I can make sure it faces forward? KT120

[rake]

The 14 ga would surely be sturdy.
Personally I'd also tig weld the corners.
Welded corners would really stiffen the box up.