I think some people are going to be very disappointed in the B29. Yes, it carries quite the payload and yes it can go 350mph at 28k (or whatever its best speed/alt is), but it will make the Lancaster look like a fast climber (figuratively) and it is going to be a very big target.
I see it being launched from waaaay back behind the front lines at the higher alt bases just to get it to a feasible bombing altitude. Hopefully, the perk price will be enough to make people think twice from using it as a "B29-Stuka". 
At first report of a "B29 at 20k over X, heading Y", I'll be sure and hop into a NiK2 "George" and climb on up for some late war PTO goodness. 
personally i dont feel the b29 deserves to be perked at all, sure it has a huge bombload, but its SLOW climbrate would most likely keep the b17/b24's in use. i mainly see the b29 becoming a city/HQ attacking bomber only. it wouldnt be good for base capturing really, a group of b17's could have a town droped before a b29 even got high enough for a proper bombrun. may be good for low-alt carpet bombing, but as stated it will be a HUGE target for ack/flak to hit.
if you plan on attacking b29's with nikkis for historical fun, then allow me to suggest to you the japanese way of attacking b29s
also, i demand dive flaps on my b29,. because i WILL be divebombing tiger tanks with it, just to cause the trillions of whine threads on the boards about it
