Length of ditch/pond

Unfortunately my family is moving off the lake we've lived on for the past 15 years. The new house is still only 4ish miles from the old house and the launch is 12 miles for the good one or 5 miles for the crappier one, but its fine for when the water is high... So I am not going to lose any time on the water and I can prolly keep the boat behind my neighbors house, or at my old house if one of the ppl looking at it buys it... (they're watersports oriented ppl) The new house has a pond, about 180 ft long or so, goes from about 10 ft deep to 0 at grass... this should be long enough to setup a slider or 2... correct? One real nice thing is the ability to control the depth/empty it with a stream supplying water to set posts and whatnot. I figure if I dig it out a lil more, or just wet the grass I can start on land, hit water and setup a nice 30-40 foot rail and dump the handle b4 I hit the edge at the end, or I can start on the end on like a ramp/chair and ride into the shallow end? My boys and I have had a winch in the plans for a while and this is the chance to step up and make it... What are your thoughts... should be able to get er done eh?
What do you need for lengths? figured 60 feet to the rail, 30 rail and then an outrun of 30-80ft to stop...

well if i were u i wouldn't worry to much about stopping room you can stop in 20 ft i f you have to just get on the brakes real hard but as for the slider i'd make it more like 40ft it'll give u some time to play on it and have fun. just my opinon though post some pics when ur done with the whole thing.