So I got impatient waiting for my Martian basing paint to dry and took a hot air gun to 5 of my inferno marine bases (perhaps a hairdryer would have worked). I ended up melting the bases (see photo of my shame). So I needed to replace them and I like my bases magnetized for easy storage/transport. So I painstakingly measured the GW bases and recreated them along with slots for magnets. The bases are made for 10 mm diam x 2 mm height magnets which are easily found on Amazon:

https://www.amazon.com/dp/B0CCX29DGC?psc=1&ref=ppx_yo2ov_dt_b_product_details

These bases are compatible with both the Ultimate Starter Set and Leviathon box sets. It appears the octogonal pins are the new standard for GW. These also fit my ork combat patrol but can't guarantee this will generally be the case. GW does what they do.

You can FDM print these but will likely take a bit of post processing if you are looking for a perfect finish. You might get away with a thick primer to cover the layer lines. I do prefer the weight and strength of the FDM bases compared to the resin, but those layer lines… Print on a textured plate if you want a similar top base appearance to GW's minus the ugly mold divot in the middle they have. I have included pictures of ones printed on a textured plate as well. 

For the best result, you could resin print and then prime. You could even sand a little before priming. I used Chitubox, angled each base at 45 degrees (magnet side down) and used auto light supports and got excellent prints. The picture I included of my completed minis show resin printed bases on the left and GW bases on the terminators on the right. I'm new to painting so be kind!  (-;

I think potentially the most useful part of this project is the Fusion 360 file. If you want to use a third party base topper (e.g. https://cults3d.com/en/3d-model/game/war-gaming-base-toppers), you can use the sketches to determine where to put the octagonal holes for the miniature before printing. Will prevent you from having to pin the miniature (or just rely on glue).