Need advice on which seats to switch...

DD was weighed at the dentist today and she was 39lbs... she uses 2 seats that have 40lb limits. To give you an idea of torso height, she has 1-1.5 inches in the Avenue. She will be 5 in 6 weeks.

I need to move seats around. Give me your opinion...
I have available
2 TB's...I'd prefer these in the least used vehicles, if at all.
2 Radian XTSL's
1 old style MA
1 old style BV
1 Avenue
1 Scenera
1 Generations 65
1 Evenflo Chase
1 MyRide

Currently this is how they ride:

My van - used daily
DD1 Radian, DD2 MyRide, Gen65(used 2-3 times a week for the baby sitters daughter... I need to keep something for her 4yrs 30-35lbs)

Sitters car - used daily
DD1 Radian, DD2 Old style BV

SIL's car - used 2-3 times a month
DD1 Chase, DD2 scenera

Gma - used 2-3 times a month...this one is tricky, she drives a truck with jump seats in the rear so DD has to go in the front
DD1 Avenue ...DD2 does NOT ride in this vehicle

IL's - hasn't used in the last 3-ish months
DD1 Old style MA

My thought was to let the IL's use a TB...they have DD the least. Put the Gen 65 in Gma's truck, keep her harnessed and further from the airbag. Put the Chase in my van for the sitters daughter. And put the old style MA in SIL's car. (Oh and to make this more fun, the MA and BV will expire in Nov 2011 and May 2012)

That makes the most sense right????? I'm surprised by her weight, I thought she was 35-36!

Nobody???

As long as she sits in them correctly and they would only be used for short trips, I'd be fine with an almost 5 year old who weighs almost 40 pounds using the TB a few times a month. I'd move the MA to either SIL's or Grandma's vehicle and use a TB in IL's vehicle and either SIL's or Grandma's (whichever doesn't end up with the MA). I'd put the booster in whoever's vehicle that I felt would do the best job making sure she stayed sitting correctly in a booster.