Do you still have that Guzzler? If yes, to get good results from it, make a recirculating loop, either from the tank it's feeding, but only if close, or from soon after the pump. Tap the line, and go back to just before the g2 Guzzler. In that line, either a 3/16 or a 5/16 put a valve. A needle valve is best but any valve can work. Then in use, adjust that valve so a small amount of sap recirculates. That will keep the diaphragm wet. Those pumps can run dry, but produce far better if kept wet.
If you no longer have it, I do have an Alamo 30 listed in the classifieds, but timing may not be with you. Not sure where you are in Vermont, but I'm half way between Utica and Syracuse. I ran that pump on 800 taps, off a 6.5hp Honda. I've opened the drippers so they do well. I only ran it at 19" by using vacuum controllers because it was connected to a vacuum tank. The vacuum tank was only rated for 20" so I didn't go higher.
Mountainvan uses the same pumps on releasers at 22"-24" vacuum. The secret is in the oil, they must get enough oil recirculation. I ran the pump using a 4.5 gal fuel tank. At 19" it ran about 16-17 hrs on a full tank. At that location I later switched to a 9 hp Honda, powering an Alamo 100. To my surprise that actually ran using less gas at the same 19" (vacuum tank still).
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.