First and foremost the CT Gallery has a lot of info, in case you haven't found that yet.

For the specifics that you asked for, you'll get every possible response, so, here's mine...

CDI vs Points.
CDI: no messing around, seldom fails, but if it does, it's expensive and it's a long walk back to the truck or the garage (it's not "field" repairable).
Points: Needs some adjustments or replacement over time, points are cheap, pretty easy to adjust, and easy to do field repairs.

High Altitude Adjustment Knob. (1969 - 1977).
Easy to use if you've got it.
All other CT's require a main jet change. The top of the carb float bowl needs to be removed and it's a simple replacement of main jet to a smaller size. Lately, I've been riding well above the 6,000' altitude without any change. Above 9,500-10,000 and the bike tends to "load up" the spark plug (it's too rich a fuel mixture), so changing is usually required. When I did it often, it took me about 10 minutes and gave the guys I was riding with a break. Just don't lose any parts on the dirt or gravel, take a towel or small tarp with you to lay under the bike to catch the parts you drop.

Rear Brake Lever on Left Handlebar
Glenn pioneered the customization of this and I've done it on my 1983, CT110.
Works great.
Thus IMHO it's not a factor when purchasing any year, as it can be done to any year that came from the factory without it.
And, let me tell you that it's totally worth it.

Personally, I'd not want a '69, K1 (early or late year model), as I find the air intake of that unique, "one year only" design to not let me cross the deeper streams. Just in case you travel to locations that have deeper streams, like the Pacific Northwest.

And, there are small differences between 90's & 110's that some other guys might chime in on.
I rode one of Glenn's CT90's recently and while it's only a few pounds lighter than my 110, it just felt and handled differently, not to mention the opposite shifting pattern that I had to get used to. I couldn't tell any difference in power as I could get his CT90 right up into the power band on the engine with no difficulty... to go as fast or slow as I wanted to go.

Peruse the CT Gallery and see what other things you might be looking to get or to avoid.


Paved roads, just more needless government spending...

I pick up my mail in Santa Barbara, California, USA.