Mine is the Basato 5. It's a monster. I have seen, but not used, the B4.
A 1/2" blade is ideal for resawing, and easier to tension, you do not need to go higher. Remember that the more steel there is in the blade, the more tension you need to apply, so big blades are better suited to big machines. Just because a wheel is 1" wide it does not mean that the saw can successfully tension such a wide blade, especially if it is a traditional thickness and not thin-kerf. The configuration of the teeth is much more important. Go to Ian John at Tuffsaws and ask his advice. He'll sort you out.
As for speed of change, that rather depends on you!
The first time it will take forever, but once you get used to it, you can do it in 10 minutes, no problem. Just make sure you get some excellent training!
And remember, it's worth going to the trouble of eliminating drift, so that the mitre slot becomes useable, rather than just compensating for it by skewing the fence. That is a very second-best solution.
If you do the right adjustments in the right order you will get excellent results, I am sure.
HTH
Steve