These brackets are some of the only options if you want to build your own 3/4” lids. The brackets fit well. The welds have held up for me, I know others have had pieces snap. The downside is that the shims themselves too thin for tight clearance and 2 stacked pieces are too thick. You are left to grind down one piece and you will not have enough shims to match the corner brackets. An improvement would be to include shims the correct thickness or at least double the number of shims.
These work very well however I've had a few with weak welds that cracked. I was able to repair with aluminum solder. More shims in the kit would also be nice.