I assure you, they can't be worse to mount than the Michelin Pro Race tires I just had to mount on my rims
I thought I was going to kill myself, just as you I had a problem with the last 15 cm or so
I left them in that position for a few hours, then I came back armed with tire levers and a vengeance
What worked for me was sticking one tire lever onto the rim where I couldn't get it on and literally just prying it on