IMO I wouldn't bother with it, only 10mm glass for a tank that size is a huge risk, and even if it's only half full for your turtle. My 100x30x50cm was made out of 5mm glass, and one of the panels was cracked. I got it replace, and had the tank braced and reinforced. And it was usually filled 5-10cm from the top. I did some maintainance on it one day and accidentally dropped a terracotta pot (and it wasn't from a very great height either) and it cracked.
I feel you'd be a lot better off getting a brand-new custom-made tank with nice thick glass, or just look for something that is a lot safer. But that's just my opinion