SN w/62T B-pipe and FPP waterbox

[jetskidude1113]

I have a SN Superjet w/62T, B-pipe, FA that was running mint last season. During the winter, I swap my OEM waterbox with an FPP waterbox which is w/o baffle so pretty much no backpressure (sounded great). Took it out for a test ride today and I'm now experiencing low end hesitation, during transition. Hi end is still excellent just getting there is like a light switch, hesitation and then all out. jetting is 70 low/135 hi pop off is good in the 25 range. don't know if I should go 75 low or switch back to the OEM waterbox. I want the smooth throttle transition back. anyone have experience the the SN FPP waterbox.
Thanks in advance,