I think choosing between tag masters and stock moto heavy is a good idea. There are only a few stock moto heavy karts around right now, but I wouldn’t be surprised to see a few more in the next year or two. The tag master fields are pretty healthy at the club level and maybe a little thinner at the regionals.
Where are you located? What did you think of the tag kart? I jumped right into shifter and I’m doing ok after 2 years, but I suspect my driving could have benefited from doing a year or more in tag. I have seen motocross guys pick it all up pretty quickly.
Like Greg said, local support is one of the keys to your success and you’re bound to find a fit with one of the local shops/teams.
Come on and join the fun. You’ll have a blast. Don’t be afraid to ask for more help.