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.
https://vinylnirvana.com
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.