3-phase install - what pylon to look for to gauge distance?

[Erie Fred]

If memory serves, don't you guys run a twin pahse (240/120v) system over there?

I did some work out in Nevada a few years ago which included a very educational day out with a couple of chaps from Caterpillar in LV from whom we were renting a couple of 63kva generators.

Yes, but that is the service at the building voltage.
I've seen 240 vac 440 vac and 575 (we call it 600) vac in 3 phase service.