mine is sometimes hard to get into reverse, although i never have problems shifting into first, sometimes i have to move alittle before i can get it to click into reverse all the way

 

Well, I've only driven it a short distance (test miles, I just put new head gaskets in), but so far it looks like changing the fluid made a significant difference in the shifting. Not smooth as silk but definitely better. No rejections going into either first or reverse and I didn't have to do anything like shift into fourth before first or something like that. This will sound like blaspheme, but the magic elixer is GM Synchromesh Transmission Fluid, part number 1 #12345349, get it at any GM dealer. It is a semi synthetic 75 wt gear oil formulated for manual transmissions. It is not cheap at about $15 per quart (you'll need three), but it's not like you change it every 3000 miles. You might find something similar in Auto Zone from Penzoil or Red Line for less.

Let me drive it for a week or two and see if my initial impressions are confirmed. I wish I'd tried this years ago...