If weight is a primary concern, than your fixation with AAs is a bad idea. Lithium batteries weigh less, and carry more power than AAs.
I just weighed 3 of the EBL 14500 AA form factor Li-ion batteries, 60 grams. For comparison, 3 Tenergy NiMH AAs weigh 80 grams. The Li-ion batteries will run a 436 for 10-13 hours. The NiMH batteries will run the 436 fo 8-10 hours with similar settings and traffic levels. So you get longer runtime with less weight using the Li-ion batteries vs AAs. Li-ion batteries also charge more efficiently; you can get more than 90% of the charge energy out of lithium batteries during discharge, vs ~70% with NiMH. So you can charge faster or get by with a smaller charger by using Li-ion vs NiMH.
Just something to think about.
Don't forget Jon... You didn't mention you need to rewire the battery holder to use 14500 Li-ion batt's in the 436...
If you don't you will kiss you radio goodby...
To me that's a dangerous senerial with the 14500 being the same size as AA's...
I can see people making that mistake and having three 3.7v nominal batt's in series at 11.10 volts... POOF!!!