<<I just want to be able to get 25 to 30 min flights. >>

Consider a powered glider, or the Dynaflite Butterfly.

I figure when I fly I get three 15 minute flights before I start to worry about the receiver battery. If you fly 30 minutes, and try a second flight on the same batteries, you might be stretching the limits. Not only that, but a plane that balances out a "15 minute" tank is going to move towards tail heaviness if you trim it out for a "30 minute" tank. You're going to have to decide between squirrely take offs or squirrely landings. It would be even worse with a tail dragger. To get a heavy tank in the air you'd have to balance it at the back extreme, and tail heavy is a handful in any aircraft.

The Cub is not a trainer. Landing gear is narrow, tail dragger means you need rudder input when taking off, crosswinds will ground-loop you. If you're looking for longer flights because you worry about landing an LT-40 you certainly won't like a Cub.