less / css / map generation workflow for styling custom site

Working on a large multisite with several websites, all based on child themes of Pearl.

I'm making changes in multiple less files. When I'm working locally I have grunt running to generate less / css and map files so I can see in the browser which less files I have to edit.

This workflow is from Magento docs, using grunt less and grunt watch to automagically generate css whenever I saved a less file, and it worked perfect - I thought...

But now I discover that if I generate css with :

bin/magento weltpixel:less:generate

and 

bin/magento weltpixel:css:generate --store=STORECODE

AFTER i run grunt less, then I have other results, and the map files aren't generated so in the browser I see only styles-m.css and styles-l.css so it's a mess ...

Whenever we publish for production, the last step is to run weltpixel:css:generate explaining why I had some incongruences between my local platform and production server.

So, I'm asking for : how do you build a development workflow that will let you modify some less, generate css and build corresponding map files, so you can see in development tools in the browser which less files you should modify?

sorry my bad English (Español or Svenska would have been better ;-) 

best

/javier