Those look really sharp! They are listed at 85mm, did you have to modify the mounting plate? Assuming the ITI gauges are 80 like the Veglia.....
You have to leave out the rubber grommet the OEM is mounted in.
Also the Speedhuts come with a large nut to hold it in the dash, that doesn't work either but it's easy to figure out an alternate method, I glued on a couple of bolts.

Note the Reset button jacks
Averno,
No, they don't claim to be waterproof but if they know it's for a motorcycle they silicone the glass sealing the front. That's another reason to have the reset button plugged in the back.
You only use the reset button on the tach once to set it's pulse rate so you don't need that.
The GPS speedos are a lot more money but you might like some of the added features.
The wiring is a little complicated they have a high Voltage inverter to make the dial fluoresce.
The speedo will accept any sort of a pulse input, I made my own pulse unit using a reed switch.

One thing that's a bit disconcerting at first, if you power them down with the motor running (turn the key Off) the needle stays put, that's because the movement is a stepper motor, it needs power to go down as well as up. Using the kill switch it's not a problem.
Overall I'm very pleased with mine.