I remixed Papalumpis A1 spool holder wall mount, removed the screw-holes and added a Honeycomb Storage Wall Dual Connector do store my spool holder on my HSW.

The short version is closer to the HSW. 

The long version is designed with a little more space to the HSW, to keep the rubber cap on the A1 spool holders unused side.

I used simply PLA, 3 walls and 15% Gyroid infill and also a little support painted on the bottom.

I printed it laying to not have the connector on seperate layers causing breaking between the layers - everything should be reliable this way.

This is my first published 3D model, so please the not perfect model. 

The main part is - it works!