3D Printing Centre Caps

I ordered a new set of 14" Minilites but didn't like the push through centre caps that came with them.  They push through by just over 40mm and didn't look right.  So having wanted to try some 3D printing for a while I have built a crude (24 segment) centre cap in sketch up and sent it for printing as a trial.  If it seems like it may be the answers I'll smooth it up in Blender and get it printed to a higher resolution.

So the 3D printed prototype arrived, see the pictures below.  My first thoughts :

1. The printing is very accurate as the facets of the 3D model has shown up clearly.  This will mean a new model using 100 or maybe more segments for the circles and curves.  

2. The surface finish is quite smooth and so maybe a switch to the 100 micron material will give a smoother finish.  This prototype was a 200 micron material.

3. The legs have been hollowed out.  That is something the software does which is clever with regards saving material, but not so clever with regards removing the strength where it is needed.  One leg broke just putting the unit in the wheel once.  

4. The dimensions are spot on with the exception of 0.5mm needs to come off where the leg clip sits against the wheel.  How repeatable this technology is I am about to find out.

5. The inside of the seven is very rough.  I guess the software needs to add another face to where the seven has been removed.  On the other hand my plans are to fill this void with an enamel which will hide the lines of the print.