You have to do what you're comfortable with. Having said that, you've already done some dose changing in response to Smoky's BG when you had to lower it because of a surprise BG number. He's responding well to ProZinc and I think the effective dose will get lower over time. Just keep filling in your SS and posting here for an opinion.
As for how often to get blood work done, I think it depends on how Smoky is doing. My vet has recommended every 6 months for Teasel. Maybe once after 3 months for Smoky because he had a hard time earlier on and then after 6 months if all goes well? Could your budget handle that?