I probably would not recommend you back cutting the turbine or reducing the diameter of the wheel as that will kill your turbine efficiency and boost level you can make.
I have only ever used Garrett BB cores and Turbo's they at the boost I set up on cars seem to live pretty well, but I never had a problem with journal bearing types either I just liked the logged response better on a BB unit, transient is where I have measured it being best, 4th gear onwards the differences can be minimal to justify the cost increases associated with buying them in the first place.
Street porting really does kill the mid range & response on a rotary engine, the problem with trying to pick this back up with smaller turbines is you really kill the engine and turbo, higher turbine inlet pressure to inlet manifold pressure and resulting higher EGT is common place. In a perfect world you could resort back to stock standard porting and run a larger A/R and alleviate the stress on the motor and the turbine long term, and have a much more
responsive engine that will still rev to 8500rpm when needed (say to do 210mph in top gear
)
In your case you would need to maybe run a smaller turbine housing (0.82 A/R) divided with a divided manifold, stay with the H trim 58mm compressor wheel and run a good electronic boost controller (Blitz I color works great!) and all of these things combined would offset the lack of mid range power you yearn for on the street. Many years ago I changed out a customers set up on his RX3 running a T2 street ported block from a 0.96A/R to a 1.32A/R set up and even though it was an auto trans it sucked ass! the turbine spec was a miss match for that engine specification. Great thing about T04's is the housings are available and cheap and you can experiment on your set up to test what works best, sure sometimes you may need to dick around with the exhaust outlet etc, but it could be worth the trouble for you. I'd still stick with the T04 frame turbo, these are a work horse and been around since the 70's!....... ideal frame size for a 13B engine.
Just trim out that turbine to get the characteristics you are after to match you engine set up.