Can't say how well they work on ejector guns.

I use the gauge mates in my 10 to 12..I don't care for the 12 to 20's. I think it's too big a jump down in size.

I think the full length Brileys are the way to go on an old English SxS 12 ga. as most English guns are lightweight to start with.
The hammer gun I plan on having a set made for weighs in at about 6 lbs.