Sounds like the first parts you get to buy are going to be clutch linkage assemblies. I would go to a junkyard and at least look at the setup, or look in a shop manual. My guess is that your homemade linkage does not have tuning range that the stock one did and because of this you are unable to get the setting you desire.
I just looked at your pics on webshots. First off, cool truck! I have a 61 2wd, love that year. Looks like you have a lot of work cut out for you, not a bad thing mine is that way too.
After looking at your pics it is pretty obvious that is not a stock assembly. It looks like one of those jobs that was meant to get the truck home and not much more. If I were you I would think seriously about replacing that assembly. I know it sounds daunting, but it really isn' too tough. I had to redo most of the linkage in my '61 a couple years back, due to rust and wear. I think that you will be happiest with a new setup, it will give you the desired adjustment capability as well as the feeling that comes with reliable parts.
I would find a donor truck, should be easy enough. First off take pictures and draw a few diagrams so you remember how it looks put together and then strip it off the old truck. Use your pictures, diagrams, and a shop manual to install the "new" parts in your truck.
Personally I would not feel safe with that clutch assembly. If it does not allow proper adjustment then you are most likely going to experience frequent problems along with short clutch life. An out of whack clutch can make a nice truck into a pain in the butt.
I hope that I have not discouraged you, this type of work is what old trucks are all about. Taking stuff apart is the best way to learn how it works.
Also, check out "LMC Truck" they offer a lot of good parts for these trucks. I have bought quite a few parts from them. Don't forget about your local NAPA though, I try to do as much business with my local guy as I can. It is a good practice that I picked up a while back. Their parts may cost a littl more but they typically have them in stock and you don't have to pay shipping.
Lastly, good luck and have fun with that old truck. You can check my 61 out through the link at the bottom of my signature on this post. Have fun!!!
Kyle
