I actually have similar type of loupes, Surgitel 3.5x mag w/ my glasses prescription built into it. They are heavier than I expected so to compensate I just added on 2 layers of the thin nose pads that come with your loupes. It's not ideal but it's definitely helped.
Make sure you tighten the rope and have comfortable padding for your nose. If you are not happy with your loupes you should exchange them for more comfortable frame. I beleive there is six months exchange option with Surgitel
It might not be that helpful, but I have never been a fan of "cool" loupes like Oakleys, because they are not designed to hold the weight of the telescopes. They work fine for some people, but never fit my face.
I had DFV nike frames for years, and when I switched them out to the old buddy holly frames, it made a huge difference.