scissorhands

I have an FC turbo II trans in the FB I'm building and it is very hard to shift into gear most of the time. Quick shifting is essentially impossible on all gears. First gear and reverse are the biggest problems. Sometimes I just can't get into first gear unless I shove it with some force. I would blame it on synchros, but there is no grinding noise at all, double clutching doesn't help, and this problem affects all of the gears (to varying extents). The problem doesn't go away when the gearbox is warmed up; I drove it for about an hour last weekend and shifts were still difficult and inconsistent.

Most of the time, I can get into any gear when the car is running by just gently pushing the shifter into the gate; after 10-30 seconds it will slide smoothly into place.

Sometimes when shifting out of second gear, the shifter "pops" out of gear with some force when I just barely touch it. This makes me think that some linkage is bent.

I have Lucas 75w90 GL-5 transmission fluid in it (marked as safe for synchros), which I believe is what the FSM specifies. I put it in about a month ago (have driven about 50 miles). I have been told to try much lighter weight Redline fluid to try and fix the problem. I'm inclined to try this because it's a lot easier than pulling the transmission and opening it up, though I would expect the factory spec oil weight should work perfectly.I have also heard that this might be a failing slave cylinder. I have bled my clutch hydraulic system recently and can see the master cylinder is working. Is there an easy way to test the slave? It's extremely accessible in my car.Also, the transmission might be mounted on a slight tilt with the tail end up a couple of degrees from the front (visual estimate), because I am using the FB GSL transmission mount.

Thanks for any help.