I really can't tell you if the additional throat space would make a big difference, but I would suggest that you keep your #1+. I used to own a #1+ and traded up to the Designer SE several years ago. I don't wrestling large projects to quilt them, so I send them to a LongArm quilter.
I fear that the #1+ would not have a big trade-in allowance at this point, so it probably is worth more to you than it would be to a dealer. (It is a great machine) You might want to call a dealer to see what they would give you for it.
Good luck.