My best results were when I rotated 90° so it was standing tall & printed with supports "everywhere". It was easier to clean up. If printing with soluable supports, print it like it is, as it will print in under an hour.
I did the OPTIMAL settings in Prusa Slic3r. .15 layer height.
You will need 3mm x 1mm magnets. I picked up a 100 of them on ebay for just a few dollars.