I know I'm a few days late into this thread, but for what it's worth, I've used the same Yankee 4x5 tank since the early seventies and have never had a lick of trouble with it. I use it anytime I don't feel like sitting in the dark, and my only complaint is the amount of chems it takes. Usually I use it when using Gainer's vit C developer with APX 100. It's a very low cost developer, and 55 oz probably costs less than a quarter. I always presoak and agitate side to side for ten seconds per min. Fairly vigorous agitation, sometimes slopping a little liquid out of the joint between the top and the tank. I also tap the tank on the counter a couple of times at the beginning of the presoak and dev time to knock loose any air bubbles. I have never had streaks, drag marks or any other problems that some folks seem to have.

Dean