This is a balance of easy ( for me ) to make and the MANY smart folks discussing. I chose Poron 1/4 foam separators in a oak box with neoprene side / bottom cushions the "front" is easy to disassemble for upgrades ( bms , cells maybe ) the case compresses the foam by 25%, the bus bars (72mm flex ) needed a very slight maybe 1 mm hone to fit. I will add the remaining cover with a 140mm temp activated Nashua PC fan ( 12 volt 3 pin ) about 30$ for fan/temp controller and 5amp 48->12 converter if the temps are an issue but my basement is a steady 65 all year so probably no need the holes and gaps in foam should provide airflow. The length was set and the bottom spacing is set to 25% compression ( 0.56 " ). Still some cleanup and tuning the BMS but it's alive and ready for it's first charge. !! Used oak and extra bracing and some crazy strong and flexible polyurethane adhesive instead of steel rods ( I'll add them if needed but I don't expect to ).