Grinding when shifting -sometimes-

Mine doesn't.

Shifter linkage or a sloppy shifter would not cause the grinding. Clutch adjustment or something inside the trans.

Yep, the statement he made about "catching right away"
(I'm assumng that means the car starts to move right after the pedal starts up off the bootom of it's travel/
That usually means the clutch is just barely disengaging and it's not allowing the clutch disc and input shaft to stop spinning before it goes into gear, so it crunches going into 1'st and reverse.