I think the bottom line on this thread is you have to experiment a little depending on the characteristics of the towing boat and the towed boat. Most outboards, on flatter bottom boats like my Whaler, and lighter boats like some inflatables, you can just dip the skeg into the water a tad, the prop never gets involved. Has made a big difference when we were towing these sorts of boats. But on deeper V tenders, that becomes less and less necessary. The slower you go, the simpler the rig can be. Consult the tender manufacturer to ensure that bow eye is robust enough especially if you are going to be in a seaway or going north of "trawler" speeds. We towed the Whaler through some bad to really awful stuff at 9 knots a variety of times and everything held up.
"There's the Right Way, the Wrong Way, and what some guy says he's gotten away with"