I'm trying to put all these ideas together.  My GMS came with a standard baffled muffler and not the "tower" muffler.  It appears that exhaust pressure is good in the tank based on what I can see in the tank and that I don't have to excessively richen it on the ground.  I can see the point of putting the tank as close as possible to the engine, but don't see an issue with tank height because the plane will be high alpha flight most of the time anyway.  I'm definitely not one to brag about making cheap equipment work fine; I've learned as with most things it's either buy right the first time or end up buying twice.  I built this plane as an experiment because I had the equipment laying around in storage.  If this were a well built 3D plane, I would probably rather put a 4 stroke on it.  I like the instant torque rather than waiting on the 2 stroke to wind up.  I've seen enough videos of this plane to realize people are making it work fine.  This engine actually has much better transition and mid range (when level) than my just broken in os 46fx.  It doesn't seem to matter whether it is an APC 11x6 or 12x4, they both spin and transition well.  I already broke the 12.25x3.75 that I had used on this engine a few years ago when on the extra.<div>
</div><div>The next 2 things I will try:</div><div>
</div><div>1. LSN tweaking.  It seems at WOT to be leaning to peak when pointed vertical and maintains well without sagging.  The issue comes up at mid range.  I found when playing with the finicky OS the other day that the LSN adjustment had a huge effect on mid range.  If it was even the slightest bit rich, the mid range would load up.  Therefore, if this one is dying at mid range without warning, it leads me to think that it may be lean on the LSN setting.</div><div>
</div><div>2. Glow plug.  When playing with this engine on the ground a couple of days ago, it would seem to tune great at low and high speed and then randomly quit when the throttle was advanced.  After about 15 minutes of back and forth with the LSN, I changed to a "newer" OS 8 glow plug and got much better results.  Maybe I will try an OS #6 (A3) glow plug if I can find one locally.</div><div>
</div><div>Thanks again for the comments.  If I was setting up for an everyday flyer, I would have set up my equipment for success, including a well built plane that I can fly rather than constantly tweaking.  Even though this one is fun, it still flies like a chunk of plastic.  This one is for an experiment and so I can get my tinkering "fix" when needed.  </div>