Medusa Afterburner V2 BL motors

Ahh the long awaited 70 mm motors are finally almost here! The 80s are a surprise tho, I had no idea they were doing them. Also, the 2 new 60mm ones are a nice addition too.

Wasn't sure if I should make a new thread or in here. Its a motor question, so I opted to put it in here, so I apologize in advance if it should have gone in a new thread.

Anyway, I have a question for you gents. I have the following packs and run this setup:

2 x 4s1p A123 packs, and 2 x 3s1p A123 packs

Kyosho Inferno ST-RR
MMM v1 - still going, fingers crossed
15/50 gearing with a Feigao 8XL 2084kv
4s2p A123

This setup currently lasts about 13min of race style driving. This was excellent when my club was running 6min heats and a 10min main. Having now switched to 10min heats, and 20 or 25min finals, its now a pain in the ass.

With only 2 4s packs, I can only do about half the final and then run out of packs. I was thinking that if I can run 7s1p packs and get 13-15 min out of them, then I can have a pack to change for the 2nd half of a 20min race. A 7s1p 2300mah A123 pack is equivalent to a 6s LiPo (same charged voltage, slightly higher nominal voltage).

Which 70 (or 80)mm Medusa should I be looking at to achieve my goal of getting 12-15min (or higher) run times from a 7s1p pack. Also, what gearing should I be looking at? I've got pinions from 12t - 17t.

I was thinking the 1600kv or the 2000kv 70mm.
Any thoughts would be greatly appreciated, thanks guys.

Oh yea, does anyone have an idea of when they'll be shipping the pre-orders?