What to put on these threads?

Rapid Robert said
. I search for one that has a wide a flange as possible (most are too narrow), not sure why, I think that'd be a (mfr) no brainer .

Same reason they put12 mm heads on bolts that 20 years ago had a 13mm head, some beancounter figured out a way to use less material, and make a cheaper part that sells for the same price