Yeah, you'll need a bladder or pacifier tank to give you the pressure needed to ensure an even run over more than a couple of inches and for when using more than around a half oz. Even the bigger glow engines won't tolerate the tank being more than a couple of inches away from the carb or within a certain size range. I recall from flying .20's and .25's for a lot of years on 4oz tanks that even with the top front of the tank being 1/4" above the needle valve and tucked in tight as I could to the engine that I'd have to land and open the needle about half to 2/3's of the way through the tank to keep peak power.
The good news is that you can easily make a "pen bladder" tank from a piece of thin wall tubing you can find at any fishing store. They sell a black latex thin wall tube. close up the one end with a plug of some sort and some copper wire binding. On the other end make a plug from some fuel tubing and a piece of brass tube to connect to the delivery line. This will be enough pressure that you can get away with a 6 to 7" run as well as run up around 2 to maybe 3 oz. You just need to make the bladder longer so it doesn't try to overfill.
With a tubing bladder what you get is that it first fills and expands into a ball. Then as you continue to fill the ball turns into a wiener. What you want to avoid is overfilling past the point where the long wiener reaches the rear plug. Between the long but not over stretched wiener shape and the final ball the pressure will stay constant. At the end it'll go slobbery rich and then lean out and cut in short order.