Good luck finding accurate installed dimensions for any of these tires, regardless of flavor...8, 10 or 12 inch. There's a world of difference between the nominal & real-world sizes and the nominal specs are scarce enough. 12-inch is becoming more popular and that carries the same issues as newer car tires; you're limited to the same tire diameter which translates into shorter sidewalls. As for wheel & hub weight specs, if there are any they're among the best-kept secrets in the biz, in the past 2 decades I've seen exactly...none.
With 10" tires, I've seen them as short as ~53" circumference and as tall as ~61". That's a diameter range of ~17-20". Stepping up to 12-inchers, on a CT70, doesn't change much except sidewall height; there's only so much real estate. The tallest 10-inch tires 120/90-10 cause some issues...reduced suspension clearance and loss of chain adjustment range. Any taller and you'll have to start re-engineering the rolling chassis. A lot of guys like low-profile tires. I'm indifferent...don't care one way or the other, in terms of aesthetics. In practical terms, shorter sidewalls have some big drawbacks. And the small diameter tires to which we are restricted mean harsher ride quality and more impact being transmitted into the rolling chassis, i.e. potential for bent rims, tweaked hubs, bent shock mounts etc. Tire sidewalls are a a critical part of the suspension of these little bikes. The stiffer the sidewalls, the more work has to be done by the suspension and real suspension components are really expensive.
IMO, you should start by setting an overall goal. From there, it'll be time to consider practical parameters...like suspension clearance, at full compression. If a tire makes contact with any part of the chassis at full compression (i.e. bottomed-out), or sooner, the wheel will lock...and disaster will follow. I'd also consider the wheel & hub combo. Stock hubs can be used, as long as the wheels selected have the matching bolt pattern. CT70 hubs are okay, but not all that great and leave you stuck with some compromises. Up front, the speedo drive can be handy it's also cheap; but, you're limited to ~56" tire circumference, if you want accurate speedo input. There are aftermarket speedo drives but, any mechanical drive is only accurate with one, specific, tire diameter. Out back, the rubber-mounted sprocket assembly is a huge plus, far better than the rigid-mount of the Z50. On the other hand, it's kinda sloppy, does eventually wear out and leaves you married to CT70 (4-post) sprockets.
If you want lightweight wheels, go for stamped rims, such as split rims from G`Craft, Kitaco, et al, if you can find them. If you want strong rims, opt for castings...which will be heavier. There's even more weight difference between tires. Stock Trailwings are among the lightest tires, tubeless road tires, with reinforced sidewalls can easily weigh more than twice as much. There is some disagreement as to which is "better". Lightweight rims + tires make the suspension more responsive, at the cost of less "gyroscopic effect" at speed, i.e. straight-line stability, at speed. These little bikes are inherently twitchy. What's your priority list? How fast do you plan on rolling along and for how many miles at a shot? How are your local roads...smooth or cratered?
As for brakes, take your pick. As long as the hub fits the wheel and the brake plate matches the hub, all you need are the proper length spacers and a solid brake stay, to prevent the brake plate from rotating when you grab a handful of brakes. Braking power is pretty much the same from the Z50 up to the CT110...same size brake shoes. An hydraulic disc brake, on the front, is a good upgrade for 50mph+ road use.
I'm cutting this here as the topic is a can of worms. It's not impossible to sort through, by any means. When building a custom bike, rolling chassis mods involve a lot of "roll-your-own" elements. The high-end parts market is extremely thin in the US of A, always has been. Most owners make their choices based on appearances and price; naturally, that's where the vendors have things covered..which makes sense. I mean, who in their right mind would stock items that cannot be sold quickly enough to pay for themselves? So, I'll repeat my basic approach...set a goal, then your top priorities (including a budget); the rest of the project will more or less dictate itself from there.
