I’m not sure 100 Ton has this one right. I don’t think you can upgrade to 2/M, then crossover with strictly tug time. It sounds like you have zero unlimited seatime. I’m in kind of the same situation as you. Graduated from an academy two and a half years ago. All my time is on tugs. I just got approved to test for my 1600 Ton Master Oceans, but it is the full 7 module test (same as the 3/M Unlimited test we took at school). I would say renew your Third Mate, then send in an app to upgrade to 1600 Master.
Unless “married” means you’re on an ATB? then it might be a different story