It doesn't matter which one you spend most of your time in but make sure you get the chance to fly both. This will help you adapt to a different plane (your -9A) when you have to.
I have a little over 400 hours TT but those are divided between over 40 different makes and models. If someone offers you a ride, and you trust your life with them, take the ride. Ask to fly it some. Try some stalls, flaps up & down, power on and off. Do a lot of turns, play with the systems (change fuel tanks, mess with the prop, trim, etc.) Don't do anything crazy, be safe, have fun, and learn, learn , learn!
While getting my PPL in a 152 my instructor had a Lance and he let me fly that a few times. A few weeks after getting my PPL one of the airport bums mentioned he handn't flown in a 150 (the club plane I was then flying.) in years. After giving him a ride in the 150 he took me up in his turbo 210 and let me fly it all around. Cost of his ride in the 150 (in 87 dollars) was $21/hr. Cost of my ride in his T210? God only knows but we flew for two hours. That T210 felt like a tank next to the 150. You get the idea. Fly, fly, fly & build, build, build!
Good luck with both the PPL and the RV.