Grades you'd take for Topps vs OPC vs Venezuela

[MCoxon]

I'm a player collector and have finished most of the mainstream runs, am now about 50% through OPC runs, and am starting on Venezuela runs.

I'm only curious and thought it would be interesting to see how others would collect these, adjusting for condition. In other words, what's the grade "delta" that would make the cards "equally attractive" in your eyes. Especially given scarcity and condition-sensitivity, particularly for Venezuelans

Example: 1968 Hank Aaron. To make these equal in my eyes:

** 68 Topps Aaron PSA 7 = 68 OPC PSA 6 = 68 Venezuela PSA 4 **

So, a 1-grade delta between Topps and OPC makes me think they're equally worthwhile, and I'd go 2-3 grades lower on Venezuelans.

I'm sure I could look at price differences and see how the market views it; but what do you collectors think?