I drew inspiration from Joosdt's very nice A1 Hotend Holders for HSW, specifically the cutout at the bottom of the box. Apart from that, this is 100% original work on my part.
I'm in the process of converting from HSW to Multiboard, and at the same time, decided to get away from the individual holders and create a single holder that houses 4 hotends, so in my case, 0.2, 0.4, 0.6, and 0.8mm. I keep 2 sets of hotends around, 1 for PLA, another for PETG, hence the multiple models. There's also a no-label version, as well as the Fusion archive. If you plan on using the labeled versions, you'll want to have an AMS, MMU, or similar media changer, or something with multiple toolheads like a Prusa XL (lucky you!).
Be aware - these use the Multiconnect connector, so as to maintain compatibility with both Multiboard as well as HSW.
I printed these in eSun PLA+ with a 0.4mm nozzle, 0.2mm layer height, and 15% infill. No supports are needed.