Electric is a good option for the Senior, and a 4S setup should work well. My other Senior is electric and is running on a big 5,000mAh 5S. Once airborne it cruises at well under 1/2 throttle and will easily fly for over 12 minutes with a big reserve of power.
Changing the design to a 2-piece wing should be fairly easy for you, I look forward to your design changes, and may be able to use your ideas when I eventually build my 150% scale Senior.
How much all up does your electrified version weigh? What motor/KV/prop are you running? Call it crazy but I'd love to try a 3 or 4 blade prop just for grins.
Looking into 2 piece wing. I'm pretty sure I have some aluminum tube that will work. If not I have tons of 450 size heli CF tail booms that should do just fine and be very light.