Neither Open Rocket or RockSim currently have the ability to correct for this known aerodynamic effect. For the worst case scenario with the fins aligned, I ran the simulations without the control fins in place and looked at the models stability. The stability margin on the Sasha with an E12-6 becomes 0.74 and 1.10 with a D12-5. The ESAM-58 gives a stability margin of 0.74 on a C6-5 and 0.96 with a B6-4. Both of these simulations assume that the control fin set is not in place and don't take into account the fins weight, so the stability margin should even be worse. Since I am an experimentalist I suggest you build the model(s) with the fins aligned and make a flight as above where I suggest the stability margin is much less than 1 (E12-6 in Sasha and C6-5 in ESAM-58) and let us know how it goes. There is nothing like a real world proof of concept.

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Bruce S. Levison, NAR #69055