Mr, Chapman, I am going to try and be constructive here. First it would be helpful if you could post some pictures of your setup. This would give us a much clear picture so to speak.
There will be other very respectable knowledgeable people that might disagree with me on this but I would suggest you drop your electrolyte to 2% by weight and work up from there and do not use a PWM. You need just a very little HHO for this engine especially since you can not adjust anything. Somewhere between 250 mlpm to 500 mlpm. This will also bring up the efficiency your reactor. You should be able to do at least a few more tests before you throw in the rag. I would not be so persistent if I was not absolutely sure that some gain is possible. Please do not take this as a personal attack but your claims that this is all bogus, when a lot of us know for a fact it isn't is hard to take.
RustyLugNut, I posted this not seeing yours. Excellent post.