Thanks for the link to the replacement fuel reservoirs. I like that they have upgraded to polypropylene. That seems a better material than the old (styrene?) ones that would eventually craze, crack, and get gummy.
Here's a good pop tester candidate for you. Checks the important boxes: aluminum body, nice gauge (huge dial!) with fine gradations in the correct range, free shipping.
https://www.ebay.com/itm/353814970320