I am not aware of any file size limits on thingiverse, I have not done anything to compress the files in any way. Perhaps it is a setting in freecad, I am new to using the software.

On the nosecap, I made a whole new one this morning which starts with a cylinder and trims away pieces until I get the shape that I want. So that the resultant 3d piece is a single piece. The pieces that I have made so far have all been primitives stacked on top of each other at exactly the defining borders between them, After creation I gather them all up and make a union in freecad. So i have printed the new nosecap however I will not post it till I have tried it in a nose cone, which I am currently printing.

I am pretty sure now that the faceting issue that you have noticed has to be an artifact with how freecad handles circular interpolation. Instead of a smooth curve, it converts it to a spline style of object.