Chris21010
radiator size is states to be able to hold up to three 120mm or three 140mm fans. so radiator sizes of 120, 140, 240, 280, 360, and 420 are all supported on both top and right side. someone also said that there is 60mm from the top of the motherboard to the bottom of the fan housing, so there a max radiator thickness of 45mm would be safe. remember the fans are in the upper part of the case and not underneath the radiator. as for the front i would assume that 45mm would be a safe bet as well but would like for someone to verify.
I'll verify all the sizes for you guys but from what I can remember last night there is massive amounts of space in the front for a super thick radiator but that would depend on if you are going to put a tube res there or not. I have a few tube res and radiators around and will get a good idea on it. All this would depend on the thickness of the fan also.
One thing about the upper slot, not sure about the front slot. It is not flat metal where you mount the radiator on I guess done for structure strength. With that said don't expect your screws to fit that come with AIO units because it is going to fall short most likely, my AIO Silverstone sure did but I do a ton of rigs with full custom loops and such so I have plenty of spare parts including different size screws and lengths. I estimate the mounting thickness to be around 4mm because of it. Again I will verify the top and front.