'Lo' rates will help but it depends just how much the throws are reduced. I'm not familiar with the DX5e.. can you program in the degree of throw reduction?
'standard' low throws would likely only reduce movement to about 80% and with no option for exponential then the Su will still be a handful to fly. A Tx with expo is highly desirable for the Su26, many would say compulsory.
Reducing throws mechanically is not straightforward because the servos are linear travel so no option for using a shorter arm. Reducing throw at the aileron horn is not easy either due to the peculiar lever arm arrangement used.
I dare say with practice you would grow accustomed to the extreme sensitivity but the first few flights might be hair raising. When I first tried my Su after a while off RC I honestly thought I'd forgotten how to fly, it was that hard to control. With the controls set up properly and plenty of expo dialled in it's transformed.