Cliff
I have the TS75 for exactly the use you need. It does nice work, but they are wicked expensive.
If you run into the problem again, flip the track around and use the back side of the guide track as a reference fence for a regular circular saw. You'll need the clamps and maybe a few in the middle so that the saw base doesn't force it's way under the track.
It sounds as if you're using rough cut lumber, and the sawyer was maybe a little generous with the 8/4 dimension. A TS55 can cut through dimensioned 8/4, and the gullets will be exposed underneath. Doesn't help you with your current problem though.