I don't know for a fact, but VPI's choice to make their platters 11.5" in diameter may have been to prevent the lips of LP's to raise the outer portion of the groove (each LP side contains only one long groove) off the platter.
Is There a New Record Pressing Machine Out There?
I bought Wilco's newest Album "Cousin" yesterday and noticed something I have never seen before, the record has no lip. The label area remains raised but otherwise the record is dead flat. It is a very heavy record, probably 200 gm. I believe records had the lip to prevent the tonearm from floating off the edge with changers which were way more popular than manuals back in the 40s, 50s and early 60's. With manuals the flat record is easier to cue by hand.