Just a quick Shower vs. Tub studio update: I finally just got confirmation that room 4115 does have a tub, despite being Handicapped Accessible, and I have updated the room location map
here.
With this change, I feel that we have a good feel for where all of the tub rooms are located. If all 31 studios on the first floor have tubs, plus the 6 higher floor alternate studios, we can account for all 37 of the studios with tubs. Booking a tub studio would give you a chance at getting an alternate studio, but you are substantially increasing your chances of being on the first floor. For a 2 bedroom lockoff I like the odds a little more, since 7 of the 8 possible rooms contain alternate studios and only 2 of the 8 possible rooms are on the first floor, but I'm not sure if I'd take the chance to go for it.
As always I will be watching reports and declarations to confirm and update the map, but I think we are very close now. Thanks to everyone who has contributed by sharing information.