That blazer is nice!! Being in such nice condition don't you garage it anyway when it rains?
If you can get some drip caps for your doors, that will help a little ity bit.
It will leak when driving as the water finds a way in any which way it can. But it did this for me with my hard top too. For the door windows, when parked and I know it is going to rain, say overnight, I pop that last button, roll my windows up, close my doors and then put the button back with the canvas over the door windows.
When driving it around while raining I bring a towel or two and that seams to do the trick for me. I guess what I am saying is the soft top performs no worse than my hardtop did, yet I can really enjoy the nice weather which makes it worth it for me. I don't think you are missing anything or have it installed wrong with how you have it.
-Jacob