I find the DSD saddles easiest to get a good seal, but do not over tighten them, if one leaks just tighten it a little. To seal the far end I suggest you put a ball valve there. A barb style works best, but if you don't find a barbed 1/2" ball valve, use an IPS (iron pipe size, female threads) ball valve and a barb x MPT adapter (male pipe thread) Then as a safety a threaded plug is good. Put teflon thread tape or thread dope on all threaded fittings. Then after the season, use that valve to clean the line.
Dave Klish, I recently ordered a 2x6 wood fired evaporator from A&A Sheet Metal which I will be converting to oil fired
Now have solar, 2x6 finish pan, 5 bank 7x7 filter press, large water jacketed bottler, and tankless water heater.
Recently bought another Gingerich RO, this one was a 125, but a second membrane was added thus is a 250, like I had.
After running a 2x3, a 2x6, 3x8 tapping from 79 taps up to 1320 all woodfired, now I'm going to a 2x6 oil fired and a 200-425 taps.