i personally do not use a filter between the tank and filter,,to eliminate a cause of air entering the carb,,my filter is on the fill tube,,as far as clunks go and the stiffness of the tubing,,you can use a big clunk or slip a nut next to the clunk for extra weight,,you wouldnt want it to flip forward anyway,during downlines,it could stay that way and pinch off the flow completely,,also it would be asvisable to either use real small zip ties at every connection,,i use snall diateer safety wire ,to secure all my tubing ,also if you like more flexible tubing,just find a dirt bike shop or small engine repair place and get some of that blue stuff thats more flexible,,but putting several filters inline may prevent a clogged inlet on your carb,but also causes more points for leaks and couldslow the flow of fuel ,resulting in less power,,ps i wouldnt reccomend putting a tee on the tank to carb line for filling either ,just use a seperate line to fill ,and you can put a clunk on that one too,so you can drain the tank if needed