I have a bunk trail and lauch at Des Moines sling. You have to have your boat bunks adjusted so that your boat will have 8 inches hanging out over the end. I did this one day while out boating it does not take much to so. Now would be the best time to do this. The other way I have seen peopled at DesMoines do there bunkers is biuld them up with with a space in the last foot of the bunk so they can slip the sling through it but make sure you make the space big enough and help them with the location of the strap while loading so it will be in the right place when they get to the trailer. This is a simlpe fix to that problem.
As for the line at Desmoines when they close Radondo bring a sleeping bag.