jim, normally I have respect for any comment offered by lewm, but here I have a different view. Unfortunately many today believe the AR is not worth considering, particularly the tone arm. But here is a full evaluation which states respect for the original design.
https://www.youtube.com/watch?v=1rgK0YMsJXM
For years George Merrill offered upgrades to the AR, but possibly no longer does. However parts and advice are offered here.
The original arm is low mass so high compliant cartridges perform best. Either finding a new stylus for your Shure or going with an appropriate Grade or AT are options. I expect the Denon 103 requires far too much mass for decent performance. And yes, overhang is adjustable, but offset is not with the original headshell.
A few years ago I restored an early AR-XA for elderly friends so they could sell it. Once completed I was pleased by the musically rewarding results.