I'm not clear on the above - do you have your manometer hooked into your pipe between your boiler & the barometric damper, or between the barometric damper & the top of your chimney? It needs to be tied in between the boiler & barometric damper. Mine is just a few inches outside of the boiler. The draft will be significantly different (more) downstream of the barometric damper, than it will be at the boiler outlet. So you might not have your baro adjusted right and your boiler might not be seeing enough draft. How tall is your chimney? Mine is 30ft, and with my baro fully closed I see 0.12" of draft at full burn. That's with no wind. If the wind is blowing at all, my baro is flapping with it. (Natural draft though). On the tanks - have you checked all the scrap yards within driving distance? I found a huge mountain of them at a scrap yard an hour away from home. They still weren't dirt cheap, but were a lot less than you're looking at - ended up somewhere around 1.25/gallon for 2-330's and one 110.