If you have a DX8, just use it and don't worry until you get stuck.
If you optimize your mechanical set up, use some matchboxes and reverse servos, I bet you can do 99.9% of available jets today on 7 to 8 channels

You can do:
1 Throttle
1 Aileron (Y, Matchbox, good geometry)
1 Elev (Y, Matchbox, reverse servo)
1 Rudder/steering (Y, Matchbox)
1 Flap (Y, Matchbox, reverse servo)
1 Retract
1 Brakes
1 Gyro

That's 8 Channels there...

if you need more, you can get creative
You can free up the brakes by mixing with elevator
or if you need airbrakes you can combine with flaps or brakes using a channel expander
You might not need a Gyro, or you might have a fixed rate one and also free a channel

My F100 was set up on 9 channels and it has flaps, slats, airbrakes, proportional brakes and a parachute!!!

So net net, if you have it, don't worry. It is doable.

But, it is soooo much easier with more channels

Hope this helps