Full plunge, no question. There is a non-zero chance of draining off of the skill shot; if the kickout is reasonable (i.e. can be bounce passed or simply caught on the right flipper), there is zero chance of draining from a full plunge. If the kickout isn't reasonable, it's almost certainly not going to be worse than the risk you take from the skill shot. I'd much rather drain through a bad flip than a magical pop bumper outlane.