Hey Darin,
I don't have any pics of the radio installation we used back then. We used Kraft radios back then and KPS-11 servos that had no torque at all. How we ever turned these things - amazes me. The "BIB GUN" servo from Kraft was the 20H I believe - still not enough torque to write home about. We used airplane aireron mounts so that the two servos would lay on their sides and get the CG as low as possible. We used penny balloons as water tight boundries. Now that the laughter has subsided - that is all we had back then.
In answer to your initial question - I would run it as you have the hardware already set up for a Nostalgic representation as the plans describe.
We used to put the rudder, throttle servos, receiver and battery pack & switch in the rear of the hull and close the rear hatch /cowl down with a lot of 4-40 screws with a rubber seal to keep water out. Pool noodles were not available back then, so we didn't use anything for flotation. Why more didn't sink to the bottom of that Racing Association of Miami's 'burrow pit' club lake - I'll never know.
For your build I would suggest a radio box that you could seal in the rear large enough for your radio equipment -1/16 birch ply or fiberglass if you can find one to fit. Put that radio box as far forward as you can get it. I would suggest an 8 ounce Sullivan Slant plastic fuel tank, close to the engine as you can get. Is that a K&B 21 in your boat or a K&B 45 - I can't tell from the pis. In either case, I'd replace that long velocity stack with an appropriate size K&B carb, and eliminate the exhaust throttle for ease of operation.
Use some pool noodles for flotation so you won't push your luck.
I would be glad to provide you any other info I can. I think we "Olde Fartes" would enjoy seeing a Mini Hoss running again, so please take and post pics/ videos if you can.
Sorry about getting off topic with your thread. CHEERS !!! Bob
I'm quite sure someone on IW will have a appropriate K&B carb for you.