Z1 Enterprises Switchblock fitment?

I'm going through some electrical work on my 1980 KZ1000 G1 Classic. Need to replace both of the handlebar switchblocks and the closest match I've found to the OEM style is sold by Z1 Enterprises. They look nice.

My concern is whether the housing of the right-hand switchblock will offer enough room for the handlebar grip to rotate freely inside it. I tried another switchblock I picked up from a local yard and the block squeezed the flange of the grip (the bit that the end of the throttle cable fits into) too tightly to allow free motion when the throttle is twisted.

I'm having trouble finding specs on the one Z1 Enterprises offers so I can compare size to my original block. Anyone know if these will fit for me?

Link is the Z1 part I'm looking at... www.z1enterprises.com/handlebar-switchblock-rh-z1-kz900.html

Any idea what model the switchblock you tried came from? Some later models had a plastic throttle tube, so I'm wondering if that could have been the problem. perhaps the switchblocks used with the plastic throttles are maybe slightly different. ???

Depending upon where and how bad it's binding, you should be able to file down the offend area. Coat the cable cam area of the throttle tube with white Lithium grease and assemble in the switch block without the cables installed. Rotate a few times. The grease will be wiped off the high spot making contact. File or sand down that area. Unless you've got severely mismatched parts, it won't take much.
Two other tips for smooth operation:
Drop a coin (nickel I think) or similar sized washer in the grip before installing it on t he throttle tube. This will keep the rubber grip from binding against the end of the handlebar. Metal on metal contact won't grab like rubber on metal
Most throttle assemblies have a large hard plastic washer that installs on the throttle tube before the grip. It sits between the inner flange of the grip and the switch block. It prevents the rubber on metal contact binding as well. Make sure to use one, even if your bike did not originally have it.

Thanks for the suggestions, MDZ1rider! Those sound like good ideas.

I have no idea where the trial switchblock actually came from....it was in a box of odds and ends and had proper wiring so I figured I'd give it a shot. I've always kind of assumed that any grips made for handlebars of one diameter will have uniform cam/flange size. I suppose not! The throttle tubes I've got are aluminum apparently. My handlebar is 7/8", I think I may buy one of those switchblocks and just cross my fingers..