Hey Debbie,
I cut and pasted a very useful reply from taikonoatama when I made an inquiry about gonbops numbers after I'd received mine a while back.As I mentioned I actually have the small and large conga and I'm more interested in the Tumba - but the quinto would be sweet too. I assume you saw the message about that from Paz - I've contacted him expressing some interest - nothing back yet - but its a free country (both our countries

- so by all means get in there!
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Keep in mind that congas sizes as a whole used to be smaller than they are these days. What you've got, really, are two congas. Here's the (original) Gon Bops size breakdown to the best of my knowledge:
"IQ" series: Quinto: 9.75"
"IC" series: Conga: 10.75"
"ICL" series: Conga (Large): 11"
"IT" series Tumba: 11.5"
"ITL" series: Tumba (Large): 12.25"
"ITXL" series: Tumba (Extra Large): 13.25"
"IT2XL" series: Tumba (Extra Extra Large): 14.25"
As far as the vintage, I don't believe your numbers alone will narrow it down as much as you'd like, as they made the Mariano (with the same model numbers) for a number of years, from, I believe, the mid 80's to mid 90's. Someone else here will no doubt have better knowledge of this last point - they could have started a bit earlier.
Also, a note on the how the size is measured, as there is some variation from maker to maker. Technically, these sizes are for the outside diameter of the shell across the top, before the bearing edge is done and the skin put on.