If you want to invest in a good quality hutch then I thoroughly recommend a kernow hutch, you'd need to collect from Cornwall, but they will last for 10 years and he custom builds them. I have three kernow set ups giving each set of my buns 90-94 square foot each. My largest hutch set up is an 8 foot by 3 foot double storey, and the runs are permantly attached.
From my experience I wouldn't give them a run of less than 9 foot as it gives them plenty of run length of get up to speed and if the buns are a medium size give at least a minimum run width of 6 foot unless Netherlands, more if they are a larger breed otherwise they can only run the length to do a binky and can't turn or hop around unless at a slow speed.
