Personally I do not think the cams are the wrong ones. The later closing should be more than made up for by boost.
I reflect back on the 2.6 turbo. To me the engine is real lazy till you get past 13lbs boost, then it becomes very happy. Granted I have not driven a stock one since 1988. and turbo boost numbers are not the same a supercharger numbers as far as boost settings.

Your torque curve is as flat as can be. Not a particularly wide powerband but that may be the torque converter not allowing the low end to show or just the way superchargers are being it is not providing enough boost down low. You made a comment that you did not feel you wanted more boost down low but from what I see the engine wants it. When I set up turbos I make sure they get full boost by 2500 revs and keep up till way past the power peak, If it is a stock engine I want the boost in below that. Your setup looks to lack the bottom boost and then dies quick after 5000 unless that was lifting off the throttle. I would expect to have full boost in by 1800 on your engine. Is your supercharger big enough? Sounds like you have it spun to the recomended max now. As far as bottom pulley it is easy enough to change the timing tab.

Now I did a tune session a few years ago with Megasquirt on a 4G63 that plain ole did not make power. The numbers looked right but the engine did not pull. That was on the MS1 chip not the MS2 you are working with. That project was put on hold so I do not have resolution yet. Best I can tell it was ignition related, an issue with many installs using wasted spark on the early MS1.The engine is running fine on Emanage still.