Hi Thomas,
I'd be more inclined to find out why your highlights created with verify labels are not showing up thick enough to see.
The best that could be done with what you're suggesting would be to turn a 2-step process of selecting the highlight line and then isolating into a 1-step process.
Could you send in your drawing using the technical support tool so that we can check out what your plan looks like after verifying the labels, why it's hard to read, and maybe see if there's a better solution available to you.
Here's how to submit a drawing with all the Land F/X project and preference set files that I'll need to run the verify labels tool and have a look.
Add a Drawing File to a Support Ticket:
https://www.landfx.com/kb/item/2312-add-file-ticket.html
Thanks,
Amanda