Ok I think I may be confused here. Are you just saying as per Randys picture it just makes it easier to use? It does look pretty awesome and professional. So whats wrong with my set up besides it does not have the ease of use?
Does muffler pressure give you the same run result as running a uniflow without pressure? (I've never used a uniflow before)
Some engines like muffler pressure, and apparently, some do not. If you have trouble with your muffler coming loose or leaky tank/hoses, then muffler pressure is not for you. The thing muffler pressure absolutely always fixes is the engine going rich when headed upwind and lean when headed downwind. I like that a lot. It's also easy to put some fuel into the cold engine by simply blocking the muffler outlet, even on a tongue muffler.
The alternative is to run a hose from the uniflow air inlet (setup just like Randy's) into the backplate cavity or similar constant pressure area. I tried pipe pressure on my OS .46VF and didn't like it very well, so rigged a bracket on the backplate to hold a tube in the BP cavity. Brett has posted that he has his plane setup so he can do this if he wants. I just do it all the time. I suspect that the NV setting might change, tho the launch rpm would likely be the same. With low winds, I didn't have the rich/lean problem, but when the wind came up, it was not fun. Others use a restriction on the uniflow air inlet, but it seems to me like it would require more experimenting, and if you lose your restrictor, you're screwed.
If you don't remember to put that cap on the bottom (overflow), then you'll have accidentally converted your tank from a Uniflow to a standard tank. The engine will run leaner as the fuel load is depleted. Sometimes that's good, but not often IMO. I never liked that. I have forgotten to cap the bottom mounted overflow tube, and that's why I suggest avoiding that setup. When you make a cap for the overflow, either put a BB in a short piece of tubing or use a rivet to plug a piece of tubing. Too many guys use a machine screw. That can leak. Some use those cute little yellow caps...fine for keeping dust out of a tank, but not trustworthy for sealing up a Uniflow tank's overflow.
Steve