That jetting will get him right on. The only problem is, he ran it lean pretty long and it had compression before but not after.
If that jetting would have been in the bike, it would have been good.
As for the popping o nthe left cylinder, I can absolutely 101% say that is because of that boost bottle coming out of the intake boot and leaning that side out. Every time I looked for some reason that left arm didn't want to stay in the crossover intake. Thus creating the popping.
1st: Compression Check. If one side is different by a large margin from the other, or very low in general on both sides, you are fried up top.
2nd: If compression checks out good, which we can only hope and pray because that kicker can be blown down with a good gust of wind, you can re-jet with the sizes we suggested.
3rd: Either keep a good eye on that boost bottle to make sure it is straight and intact, or deal with the popping and leaning on one cylinder. I personally would lose it quick... like really quick. Stock crossover tubes are $5 on ebay. I think it might be a good inverstment with your situation. Poppoing and sucking.... and that thing keeps coming off the crossover on that side.
4th: Like said before, if everything checks out, tune accordingly with starting at the jets above..... AND DOING A PLUG CHOP. Guessing games are over at this point.... if you are lucky enough to salvage that top end by re-ringing, you won't be lucky a second time by guessing and riding it knowing it isn't right.
We both know these bikes are not made to do that.
Sorry for the rant... but it disgusts me just as much as it does you. I think more so me because I know the money and time I put into my motor and I hate watching all of this take place. I laugh when a four stroke pops when on the thrttle, but I cringe when it is a banshee. And it gets me upset knowing we both knew and you were warned that this was going to happen.
Good luck and you know where I am at if you need any help.