Cougar, attached is the only picture I could find that shows any view of the pads on the dingy...you can see they are almost on the top of the tube...it was not that I wanted them there it was that this particular Merc model had a number of line holders and logo treatments glued in areas that precluded me from putting the pads in optimum spots...more specific to your questions:
1) Every instruction I see says put the pads on first and use them with the attached davit to spec the location of the plate on the platform. The extensions are extremely sturdy and offer little flex in hooking to the pad bracket...if you install the plates first and then measure to intall the pads on the tube, you do not want to be off by much or it will mess up the fit. To more specifically answer, If I buy another dingy I will check to see that I can get the pads on the rub rail and would most likely end up with 4 and 4's.
2) The snap davits, once installed, are very easy and efficient, using the removeable plate system just leaves the flat plate on the platform when I'm not using the dingy, so never really looked at the other configs...the fact that the motor fit in the transom is a bonus. I did install one 30" stand off, just above the port side of the transom hatch...don't use it much as the dingy almost lays completley flat upside down on the platform when pulled up, and if you see in the photo how I have the line throught the port tow ring on the dingy...when it is snapped in the davits and that line is attached to the port stern cleat the dingy actually balances very well at just past 90 degrees...so, when comeing into dock, the admiral just pushes the dingy out as if launching it and the line holds it up without the stand off getting in the way...if a little rough or windy she'll attach the stand off...the arc may be a great solution, just have not looked at it.
3) Originally bought from Defender in Watertown CT (if you don't know them they have a large catalog) for our 288, then bought the extension arms for the 318 direct from Weaver...not sure there was much difference in price...I will say it is some of the best made equipment you'll see, so while expensive, not a rip-off...also, my dealer has been great in buying the new swim platform plates for me each time I've moved up in size.
Thought about the "Weaver Leaver", but you may want to check out Adventure Marines Swivel Bracket...I don't have specific experience with either but have seen both...the swivel bracket looked a little better to me.
Basically looking to do the same on the 358, what I'm not sure of is how the installation of the back rail system will effect the mounting and use...if I keep the rail up all the time the dingy will have to connect to it and be in an upright position...may have to pull and stow the rail while under way to have the dingy lie flat...just more of the fun stuff to figure out.
JB
