I'd say it's close enough - especially since he was barely on insulin for six weeks.
So here's the deal: Smokey will always be diabetic, but now he's a diet controlled diabetic. That means that if at any time he starts eating higher carb food he can relapse. It also means that something as simple as a dental issue or a UTI can cause a relapse, so you want to stay on top of teeth cleanings and any emerging health issues as soon as you notice them.
Pet food makers are the worst about being transparent, so don't trust what you read on the labels. If you are ever moving to a new food, check the food list, write/call the company, ask on here -- check and double check future food choices to make absolutely sure they are okay.
As far as checking BG, I would check once/day for a few more days just because of that 152 a couple of days ago. Then you can go to testing once/week. And after about three months, you can move to once every two weeks. At that point, put it in your calendar with reminder alarms because as time goes by, it gets really easy to forget.
A relapse is much harder to get back into remission than the first time, so if he does come out of remission, you want to catch it as soon as possible and get him back on insulin. If at any point you suspect something, or notice extra drinking/peeing, test. If he's acting funny, test. If he's been stressed (your upcoming move), test.
There aren't even words for how happy I am for you and Smokey! You've done such a good job of learning about all of this and doing what he needed to get to a healthier, happier place. Congratulations to you both, and may he have many healthy, diabetes free years ahead!
Please stop by sometimes and give us updates, and share a word of encouragement for new folks as they join!