I wouldn’t recommend a bipe as a second plane but for different reasons than most. I have a Balsa USA Phaeton II and a Hog Bipe. They are almost as easy to fly as a trainer. They will fly slowly and maneuvers are stately rather than frantic. If anything landings are easier than a trainer precisely because they don’t float. Just carry a little power on approach to give whatever glide angle you want and cut it as you cross the threshold. It’s almost automatic.

The reason I wouldn’t recommend a bipe for a second airplane is more related to damage and repair. A second airplane will likely be subject to a few more hard knocks while experience is being gained. Bipes take longer to build, are a little harder to setup, there is more stuff to damage, and they are a little more fragile than a monoplane. As far as flying, if you have really mastered the LT-40 you shouldn’t have any trouble flying either of the two bipes I have. But depending on your construction/repair skills, it might be better to defer.