Dan, this muffler is a straight pipe, other than the bend required at the front to clear the tank compartment. Everything else is straight, no bend or any direction change to the stinger at the outlet end.
The outlet stinger measures about 0.56 inch OD, and the ID is about 0.46. So, a section of tubing, or a deflector with 0.50 ID, should work.
If some have experienced power loss with the deflectors, my guess it is due to too small an ID. And, the 45 degree bend might have something to do with it as well. I have looked on line for these deflectors and saw one with an ID of 11 mm, which should work OK. At least, I see no reason to believe it would cause big problems.
With hobby shops now closing up, I have to find this stuff on line. I would prefer to see the item in the flesh, maybe check the fit, before buying.