Good comments above.
I agree that my instructing career was a huge help getting to the front seat of the 744. You'll appreciate it in the training stages when the whole process will be completely familiar to you. Don't let people who don't know any different get you down.
As far as the Grade1 goes. If you've got ME training approval/instrument training approval on a grade 2 rating, there's not much more you can do with a G1. BUT in an interview, you might be asked 'so you've had the hours for a G1 for a long time but your still a G2........tell us why? Show them your always pursuing your career. The G1 is not that much work after all.
Good luck