Carbide on antique lathe again

Things have changed since I asked this, I found a Baldor-type carbide grinder and a diamond wheel for it and tightened up the worst wear on my SB Heavy 10 by surface grinding the compound base. I acquired a GTN-2 cutoff holder and a very stiff boring bar for 1/4" IC triangular inserts. Both cut the rock drill rod to a smooth finish and haven't (yet) chipped. Though annealed the steel is still hard enough to quickly dull HSS if not in back gear.
This says a solution is possible.
https://www.thegallos.com/carbide.htm
https://www.thegallos.com/response.htm
Can anyone suggest specific inserts in those sizes they know to work well on a slow worn lathe, preferably 'affordable' ones from a dealer that sells them individually like LMS? The ones I bought from an Enco store the first time I tried carbide soon chipped. They were C5 and C6 grade, maybe I should have tried C2.