That looks like an Aristocraft chassis Jon. I use one for my general purpose "translator"/battery wagon. As you say the answer is more complex - The factors, as well as wheelbase, include buffer face to axle centre distance (i.e. how far will the buffers throw out in curves), is the centre buffer articulated and how long is its shank. One of the issues with using a dumb centre buffer with chain link is the risk of the narrow buffer faces locking while shunting or propelling stock over tight radius track geometry. Other coupling types offer greater control in these types of operation.
One way you can mitigate this is by creating transitional curves, say R2 opening out to R3, where possible, rather than fixed radii. You are already half way there by using larger radius points. It also brings in the possibility of using flexi track and don't discard the possibility of using Piko's curved (LGB R3 inner, R5 outer) point. That is a handy solution if you are working in a tight space with some "larger" stock. Max
A couple of pictures of a detail of my line to illustrate. You will see we have had similar ideas to layout. All the points are R5 and most of the curves are flexi track but there are some R5 and even R3 in there. See if you can spot the curved point.
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