These are brand new goggles. I'm having trouble w/ them fitting as well, so I may go back to my old stand bys. I got new ones because I wanted mirrored lenses sinse we are swimming into the sunrise on the outbound leg.. sigh...
Go with your old ones. The ones that fit and you are use to. Don't change what you know, now.

Plus, you won't have your head out of the water that much. When you spot, you should just glance up and keep going. The sun won't be as big of a deal as you think it will be.

You are going to do great!