Mech. Temp tube routing question

[Tim240Z]

I am installing a mech temp gauge in the L31 350 in my truck. Now, in the past I have always mounted these in thermostat housing (old style V8 ). Now, with the newer engines, the sender is in the head, right by the exhaust. Since the copper tubing can't be bent to a hard bend, how close to the header is too close? I think it will end up being between 1/8" to 1/4" away from the primary tube of the header....
Can I swap places with the ECT sensor port, or will that F-up the signal to the PCM (I can't see why, but....). I would prefer to run the mech. gauge, but if necessary I will switch to an electric one......
Any thoughts......