Have You thought about Electric.
It may well be that You have a Couple of e-RC planes. but just wanted to make sure..
Electric has its +'s and -'s and one good Plus is instant power, on any kind of day, No fuss over the Fuel and Mixture, (This may be no problem to you being experienced with RC plane already). but the other bonus is the Lack of Goo everywhere. heli beat the air into submission. and the Air is usually full of Exhaust and its residue.
Good choice for going with a larger Heli. As you probably already know. larger is usually more stable. and a dam sight easier to see. the only possible down side is the Flying location and Crash expenses.
Good luck and keep a keen eye on those blades. Do some math an you will find that the tip of the blades on Heli in the range of the T-Rex 600 nitro will do some serious damage.
Bryce.
PS.
Commercial Fixed Wing or Heli ?