Soviet preset lenses and over-exposing for film

ok... So far you folks have been tremendously helpful in answering my queries .... so I thought I would run this past you.... please correct me if I am wrong.

I have a Mir 1B, a Helios 44m and a Jupiter 9 and on my Canon R6 they are amazing. Now I want to put them on my Yashica FX3 2000. So, the exposure metre on the Yashica is funny... three traffic lights, more or less but I normally metre off-camera. However.... the preset system on the lenses is cool... on the Mir 1B I can focus wide open and then stop down to the f-stop I want... and also anywhere along the way if I like the light I see in the visor. But..... if I want to over-expose....

Imagine Kodak Color ISO 200 .... should I set the ISO at 200 and just expose for the light I see or drop the ISO to 100 or 50 or whatever?

Ah, the great mysteries of life and photography!

Thanks in advance.

In my own workflow, I've found that I can get usable results of 6 stops of overexposure from color negatives with no development compensation. Even more by increasing exposure in scan and/or using simple post processing tools.