The most logical choice would be topping Laver's two CYGS seasons with three:
If someone chooses three CYGS - that player is also guaranteed at least 12 majors, at least 156 weeks at #1 and at least 3 year end #1s, though they're not record breaking by any means, those supplementary numbers would still make that person a candidate for GOAT.
If someone chose, say, individual records at any particular major - like 5 AOs or 8 FOs or 6 USOs - the supplementary achievements that go along with those records aren't very impressive - #1 ranking isn't guaranteed, other majors aren't guaranteed..
Yeah..3 cygs would be awesome. It would require some auxiliary records to cement yourr status as GOAT but the player would be remembered forever.
The weeks at no. 1 don't mean anything unless you win slams (look at wozniacki).