If you need to go a long way to get the drive head then it is infinitely better to use a larger plastic pipe to feed a small tank at the drive head with a decent steel drive pipe running down to the ram at 45 deg. It doesn't have to be very long, there is a lot of myth about all this, but to keep it very short you will need better valves than plumbing fittings. Even with your fittings as valves I doubt that you need more than 20ft of drive pipe.

Rams are very simple and incredibly effective but if you don't understand their peculiarities they can produce strange problems and many are almost certainly not working at their best because of errors in design and installation.