I think you need to pull the valve body.
Check the assembly and clearance of the throttle valve, and I think the TF-2 kit uses a different shift valve. When installing the shift valve you may need to tweek the arm that moves the shift valve so it aligns with the passages in the valve body. The instructions should show this. I also think you need to file a groove in the valve body at the shift valve location. You may also want to remove front clutch restrictor in the case. double check the pressure valve adjustment too.
Since your in the trans, re-adjust the bands.
The Sonnax oversize front servo kit helps improve the 2-3 shift by reducing leakage (the front fluid circuit that applys the front clutch also applies pressure/fluid to the front servo between the servo piston and cover to release the front band) to the with the "O"-ring sealed cover, and releasing the front band quicker on the 2-3 shift.

Transmissioncenter has these servo kits for $73, part number #518RED16:
http://www.transmissioncenter.net/727transmission.htm

The description says to use with above cover, but the kit shows the sealed cover included.