I’m sure that I am not the only one using this plug-in, but on LocalByFlywheel I have to start each site individually including my MainWP dashboard. This is not a problem, but very time-consuming, especially if you have a lot of sites.
I also use DesktopServer by SeverPress and once I start it, I only have to load my MainWP dashboard site and it will sync and update all sites without haveing to start each site individually.
It would be a great improvement if LocaByFlyheel did that also.
Same here. MainWP works great for live/deployed sites but I haven’t been able to make it work with Local so right now I also have to launch every site one at a time and update manually plugins, themes on each site being developed. Very time consuming. Flywheel should provide us with a guide on how to set it up. There must be others who would benefit from this…
As an alternative this is what I do.
I use the Volumes Add-on to link any plugin/theme being developed into the site. This allows me to keep these project separately on my computer and use the same project in multiple places. The Volumes Add-on creates a shared folder that my IDE doesn’t see inside of. You can change the created folder in your filesystem for an actual symlink and the IDE will be able to see and edit the individual files. Since it’s a symlink, it will be updated everywhere.
The only issue may be with seeing updates to your project and potentially overwriting files. I’ve written a plugin, Local Development that blocks any updates.
Personally, I’ve found the above workflow keeps everything in sync and current. If you have issues getting this set up ping me.
Thanks for sharing with us your approach!
As of this morning however, I can say that I managed to successfully connect and update all my SSL sites currently under development using Local + MainWP. I love it! 
The only thing to remember is to start the sites - otherwise they wont connect/sync with the MainWP.