I have to weigh the options available. The Trailer tongue mount looks interesting and I was worried since I have a Propride Hitch, but noticed Lantley has a Hensley and it worked just fine. My issue is that I wouldn't be able to carry the bikes without the trailer (not sure how big of a deal that is) and I believe that system is close to the cost of the Yakima Roof Mount. The front hitch is out due to 1) I have expensive bikes and don't want rock chips and bugs after a long haul and 2) I don't want air flow to my engine to be blocked.
I'll look into the Over the Tank mount, but depending on cost, looks like either 1) Yakima roof mount or 2) sticking with my current set-up (free) of dragging the bikes into my bedroom and mounting them on a homemade plywood platform with 4-forks to mount the bikes to. That's not my favorite because of the 20-30 minutes it takes to very carefully load and unload all 4 bikes (Such a hassle).