Since Servos are so cheap now (relatively!) I plan to put the aileron and flap servos in the wing in line with each control in the modern manner - so 4 (small, digital - Futaba 9650) servos in the wing - but not in the center as they did it in the 80's. I am going with the combined flap and spoiler arrangement like the earliest Curare - rather than the seperate flap and spoiler - really just to save effort and weight.

For the elevators I plan to do the same thing - putting a servo in each tailplane half (futaba 9650 again), mounted on plywood "covers" underneath each half. I use 2.4Ghz radio - so no worries about long servo leads.

So that leaves me with motor and rudder in the fuselage under the wing (remember I use electric retracts - just plugged in like servos). For the rudder I plan to use a "pull-pull" arrangement with fishing line. I am using a Futaba 9252 for that.

I think that there is plenty of room in the fus. in the space over the wing (or if , like me you mount the fuel tank there for balance you could put the tank up front where the fuel tank "should" be) for an air tank for pneumatics. The actuating valve could be mounted on the servo tray next to a retract servo (you would not need a particularly special servio just to actuate the valve). My other Curare (the one with the Webra 61 in it) has the tank mounted over the center of gravity (I used a Perry pump) so that the CG does not change as the tank empties. It works fine - but does consume space over the wing. Not such a problem with the new modern radio as it is much smaller.

I hear good things about OS engines I am sure that you will be happy with it - especially if you dont plan to use a tuned pipe al la SPA.