Running the retrieval line through the clew works well for us. It sucks the clew into the back of the chute with a heap of spin sheet. You need to cut a metre or so off your spin sheet every so often until you're happy with the length; short enough to be tidy when doused, long enough to work when hoisted.

Another system is to have a spin sheet turning block with strop shock-corded to your front beam so that when there is tension on it the shock-cord releases about a foot. Only effective for small amounts of slack take-up (1 metre max) but it will move the sheet forward on the tramp.