Have you read through the EQMOD Project site for any information about custom mounts ?
The eqascom driver was originally designed to replace the Synscan handcontroller function for most commercially made Synta mounts ( Skywatcher, Orion and some Avalon mounts ) to provide a remote PC based option of control.
Attached are my procedures to set up EQascom with Stellarium with standard Skywatcher mounts that are listed on the EQMOD site.
https://eq-mod.sourceforge.net/
As you have designed and constructed your own mount , it will probably have custom gearing and gear ratios etc… number of teeth and so ……
You may have to post your enquiry on the Google groups EQMOD website and hopefully Chris Shilito the EQMOD support developer or other folk can provide assistance
https://groups.io/g/EQMOD
Cheers
Martin