Thoes GP 2200 seem very impressive ! How would I solider them to fit 9 cells in the space the XXX4 allows ?

GP 2200 =
Length : 1.32"
Diameter : 0.89"
0.89 x 9cells = 8.01"

GP 2000 =
Length : 1.68"
Diameter : 0.66"
0.66 x 9cells = 5.94"

The GP 2000 will fit fine side by side. I have about 6.12" to work with ?
They also have a 2500mah battery at 0.66" part # CBP2500A

Also how well would the Basic XL5000 work in the XXX4, using 9 NIMH batteries or 3 cell LiPo ?