I have rebuild kits which have almost all of the parts you would need to do a rebuild. Did you mark the drive collar so it will go back on the same way as it was removed? The bottom bushing usually doesn't wear too much but the top one will. End play is correct when there's no play and the shaft turns freely. There are a number of different thicknesses of shims to find the right amount.
The advance has two parts: mechanical and vacuum. The mechanical moves about 20 degrees and the vacuum moves about 10 to give you 30 degrees total on a 051 unit. If the mechanical is under 20 degrees, or over that amount, the pull rod on the vacuum cell can be adjusted in or out to fine tune the total advance. No other adjustment is possible although the rate of advance can be adjusted by changing the tension on the springs.
The only way to get all of these things to work properly is to use a distributor tester. It will test several functions at the same time and very small adjustments are possible using this method. Using a timing light on the crank shaft isn't acurate enough because you won't be able to see the small changes like you can with a tester.