Nice work!
I definitely understand the desire to have a smaller tunnel, but, it will not make any future work on the transmission easier. I went over the top of my crossmember with the tunnel, and there is still not much room to do things like check the fluid level of the transmission or attach the pigtails for the lockout, speedometer, etc. It will also likely limit your install/removal options, as getting to some of the bellhousing bolts is difficult enough with the tunnel the way I did mine, and I actually modified a few spots specifically so I could get at peripherals and bolts after install.
My philosophy on it is that I would rather have a larger tunnel and be able to access everything I need to service on that transmission than have a smaller one that looks better but requires dropping the transmission to get at anything