Different tachometer and speedometer Questions!

Hey guys, I'm currently building an old KZ550 C3 that was neglected a bit and turned into some sort of bobber... I doubt they were able to ride it the way they had it. Anyways...I am currently looking into some new tachometer/speedometers and was wondering if anyone else here has used another motorcycle's or a brand new unit on any of their builds. Or, if there is something I SHOULD be looking for when I want to buy one...say like a Harley tach, is there a way to find out the ratio for this bike? Thanks for any help you can give. I've got a lot to do, but I want some time to find the right things.

And just so I don't get yelled at...here's some pics! The first one is how it came to me, the second was a mockup of where I think I want to go with it, that was taken 2 months ago. Its all apart and in boxes now as I get the frame cleaned up. haha

Bruno

Here is the second one.

Acewell makes a nice instrument cluster in one unit.Might check them out.bj

Thanks for the suggestion. I guess I was hoping for some thoughts on the mechanical-type. The bike came with gauges that weren't made for this bike, and were literally just sitting atop the headlight. I have no idea where they came from. I'm not sure I want to spend 300-400 on a gauge set just yet...