We used 0.28mm and it took approximately 7.5 hrs with 50% infill.
Once printed we sanded with 80 through to 600 grade sand paper and then polished with metal polish. The model came up well. We had some 3D printer artifacts, for one layer the filament got caught so there is a line that runs around the whole of the model. The other thing was that we applied too much polish in one go so that it dried in the indentations between the layers. This has apositive effect in that it adds an almost aged patina to the surface of the model but if you do not want it then we would suggest applying polish to small areas and buffing it before moving on to the next area.
We could have continued sanding but didn’t. We need to find a better way to sand the intricate detail.
But saying all that it does come out very well and looks very good as a display piece, It makes an ideal gift, which is in fact what this piece was used for.