If, when stopped, it will sometimes grind going into 1st from neutral, the problem is most likely that you just had it out of gear, clutch out, then pushed in the clutch, and tried to engage 1st. True?

If so, then the problem is actually the 1st gear synchro, not the clutch or the bushings or anything else. What's going on is that you have the clutch out, with the lever in neutral. This allows the engine to spin the input shaft, but not the output shaft. Pushing the clutch in disconnects the engine from the input shaft, but the shaft doesn't come to a halt instantly. When you try to engage gear, the 1st gear on the stopped output shaft tries to stop the still spinning input shaft. This is what the synchros do. They're effectively brakes. If the synchro is worn, the brake won't be very effective, and you'll be able to move the gear into mesh faster than the brake can slow the input shaft, and you get grinding.

The trick is to push in the clutch and wait a bit before trying to engage 1st from neutral. Engaging 3rd (which usually has a synchro in better shape, simply because it's used less and the speed differential when it is used is less than 1st) before 1st will help, as the 3rd gear synchro will be able to stop (or at least slow) the input shaft. No grinding.

If the clutch is misadjusted so it doesn't quite disengage, then it will make the problem worse, as the input shaft will never quite stop spinning, and you're forcing the synchro to make the clutch slip and stall the input shaft. This, obviously, is hard for a worn synchro to do, and wears out the synchro even faster. However, even with a perfectly adjusted clutch, you can get this problem.