Saturn Mods - the whole "pin thing"

[sv650touring]

Some Saturns have round buttons, some have oval
Some have 21-pin ribbon cables, some have 20-pin
Some have 32-pin IC's, some have 64-pin

I want to know how these relate to each other. Do all round button models have 21-pin ribbons, but either kind of IC? Things like that.

Some time ago I found a funny looking modchip in a burned out Saturn, and I finally bothered to look it up. This is the chip I found:

http://home.clara.net/robwebb/shop/saturn/saturnchipguide2.htm

On that site it said this chip is v2 of the Saturn modchip, and with just a couple of jumper changes can be made to work with most 64-pin Saturns, but it does require a 21-pin ribbon Saturn to be used. This suggests that 21-pin ribbon Saturns come in both 32 & 64-pin flavors. Do oval button Saturns ever come with 21-pin ribbon cables? Why would (based on the wording of the site) all 32-pin, but only some 64-pin models work with this modchip? The site is sellin several pre-modded oval button Saturns, so they must be moddable.

Anyway, I would just like a thread to settle this simple, yet never-made-totally-clear subject on Saturn mods. Please contribute any experiences you've had on the subject of modding Saturns other than the easy old 21-pin/32-pin/round-button model. That's the only kinda Saturn I've ever had and they were all modded.