See if I can help out. I have the TI spin and have had it out a bunch this summer. First, your lead problem with the cheek block. I noticed the same issue and found a Ronstan block to replace it. The Ronstan also is a ball bearing block, so not only is the lead better, the friction is less on the sheave. The same holes in the aka work but you do have to thread the bolts through the holes in the block, the Hobie supplied screws are very slightly too thick. Don't worry it works fine. Much improved. I think the West Marine part number on the block is RF35151. You could cut off the plastic on the inboard end of the stock block but I don't know if the block will still be strong.
I attacked my cheek block with a Dremel today, and cannot see any obvious loss of strength by cutting off that vertical bar on the inboard side. The line now runs much freer now, so I probably won't need to replace the block after all.