I have the same engine and reeds but larger pipes. I too got the answer from them about not being able to tune for 28's. I've been down the road of 35's and know for my riding area I need the fuel economy and I like the lower power. I settled on 33's taking his advice in consideration. There are plenty of folks running 28's, tuned in well and they are happy. I sometimes get buyer remorse and wish I would have stuck with 28's.
Opinions are like kittens, everyone giving them away, myself included. Cam at Redline will shake his head if you want any smaller than 35mm. Whats his name who builds CPI pipes and dynos thousands with an AFR swears you'll never be tuned right without Mikunis 🤮.
Rock the 28's if you got em!