Just as a follow on, having launched a SatV a few times - more power is necessary - the D12 recommendation is crazy to me but I understand why. At a minimum I'd make sure that you can fit an longer "E" size 24mm motor in there. In fact, I'd recommend putting a 29mm motor mount in there with 4x18 for clustering. The new PSII black powder 29mm motors are a good match for the SatV - not so thrusty that the fins will rip off but powerful enough to give it a decent ride.
Of course the fins will likely need some reinforcement and there are some other structural changes which might be a good idea, but just some food for thought.