I would not do the Sig kit. The cowl is too small and you will butcher it beyond recognition--trust me on this one. The thrust line in the Cub is a bit high as I remember for the G23- although it has been done. The Balsa USA Cub (then take out the 2-3 ribs out of the end of the wing and adjust the ailirons accordingly for clipped wing) I think is a better work around the G26. If you were to do the Sig, I have heard the RCS 1.40 or MVVS 1.6 gas would be a decent combo.