Force "Mail this web page" or "Share" to use Gmail as preferred email Client

Hi,

Since I upgraded to Mojave 10.14.2 with Safari 12.0.2 I cannot get the 

"Mail this web page" or "Share" icons in my Safari toolbar to use Gmail 

as my (desired) email Client.

The old working mailto.safariextz extension is now ignored by Safari 12.0.2

I've tried one solution that recommended using the Developer "Extension 

builder" option and going through some hoops to get the mailto.safariextz 

extension into a format that can be installed (mailto.zip and mailto.xar), but 

even with multiple tries and following instructions "to the letter" either I'm 

not versed enough, or, Safari simply will not allow one to bypass its directives.

Anyone have a solution?

Many thanks!