Deepest reach welding vise grips?

Well I found 1, "24" for a decent price (actual "vise grips") wow do they vary in price...
Should be here tomorrow. There's a guy in Wisconsin that has a pair of 24's I'm watching, wonder if he'd ship them and how long it would take... I don't want to borrow something that I might then have to pay to replace and then pay again for a tool to finish my job...
I then ordered a set of cheap knock off 18's (set = 4 pairs) off of Amazon, they'll be here today. I don't need a crazy lot of pressure fortunately, if I'm gonna cut and modify something especially most likely a "1 time deal" that's where the only time I cheap out on a tool that I need. I have plenty of 1/4x 3/4 and 1/4x1" flat bar, I'm gonna cut up these cheapies and extend those. Hopefully that "u" channel isn't cheap enough that it bends on me... I'm hoping that if I butt the flat bar against the existing flat bar inside that "u" before I weld, that it will keep that from happening.
Plan is to pinch it together with a copper backer that I have, and weld away... I want to "need" the absolute minimum amount of bondo as I don't want something in there that will absorb moisture in that seam.