integrating innerRadius / outerRadius project calls

innerRadius and outerRadius are essentially aspects of each arc.  Thus, project should go through the generateAttrToProjector which is gotten from relevant project calls.
Awkward issue I'm running into is that I'm trying to mirror these attribute points for an arc here
https://github.com/mbostock/d3/wiki/SVG-Shapes#_arc

However IAttributeToProjector's map keys are all lowercased, meaning retrieval is lowercased and setting is camelcased which is something I'm not a fan of as well.

I might be ok with r0 and r1.  Any other suggestions?