Just recently got the Michaels and there’s notable heel slip. When I’m walking with them, my heel is lifting off the insole. I’m an EU 41.5 in MM Gats, and I did a full size down for these Paraboots for 40.5. I’m concerned about there being too much space in the shoe, which is causing my foot to slide around slightly. I don’t know whether breaking it in will solve this or make it even worse. I’m contemplating going a half size down to 40 so it fits snugger and having it stretch when I’m breaking it in. However, sizing down 1.5 seems kinda excessive to me. Should I thug it out and break it in first, or should I just return it now and get a pair in 40s?