I know you stated you are only listed in those trainers, but have you considered rollers instead? I know there are drawbacks since you can't get the power readings directly from the trainer, but you work on alot more things when using rollers. You get to work on balance, smooth cadence and helps you develop riding in a very straight line so is more then just on you're power output, they do take a bit to get used to though and they put alot stress on you're bike vs a trainer.