Hi Dave,
I got a great deal on a Seaswirl a few years ago that saw duty as a ski boat, but when I got it, I quickly transformed it into a boat for the Straights, and the Sound. It has a nice deep V, and a 140hp main motor with a 6hp kicker. The 6hp will move the boat at about 5.5mph in an emergency, which it did once when I blew a lower unit, and troll for 10 hours at 2 mph using only about 2.5 gallons of gas. (I always carry 9 gallons of kicker gas)
Here is a shot of the stern section.
The black squares on either side's gunnels are the downrigger mounting plates for my Penn 600's, and I have added a nice bait station, made out of UHMW, that includes a leader holder for hootchies and pretied mooching leaders and a spot for my brined herring bucket. I added a few rod holder inserts, and a rod storage rack that I fish a rod out of when trolling at Sekiu, using a deep six.
Here is a shot of the nerve center.
I have a Hummingbird finder and an Interphase finder for different uses, a VHF marine radio, and a mount to the right of the steering wheel for my GPS. The fish cooler goes up front and out of the way.
If you have radiused gunnel tops (rounded), you could do what I have seen on other "ski boats" where they bolt a 1" thick block of aluminum through the top of the gunnel with two or three countersunk bolts in a line and then run a reinforcing brackat at a 45 degree angle to the outside of the boat. Yeah, you are drilling a hole in the outside of your boat, but if you don't brace the torque from the weight and drag on your downrigger, you'll eventually rip a hole through the top of the gunnel, or crack it.
If your gunnels tops are flat, depending on your dowriggers, you may have enough room to spread out the stress by drilling a few "custom" mounting plate holes.
Don't know about the kicker bracket, but maybe you could trim the swim step. A kicker on the end of a swim step will act as a pretty powerful lever (simple machine), and may eventually cause some stress related issues unless you remove the kicker when you trailer the boat.
Finally, how are you going to steer your boat with the kicker on it? Some folks like the "EZ Steer", but the $125+ price steered me away. I bought a product from "Goldeneye Industries" that you attach to a 3/8" stainless rod threaded on both ends using a 3/8x24 die. The stainless rod was about $5 at a metal fabrication shop, I did the custom bending in my vise, and the connectors (stainless steel) were about $40. I already had a tap and die set. Here is a shot of the connection set up, notice the new lower unit.
Using this set-up I can steer the boat with the main motor controls, using the kicker for power. It does require that you go back to the kicker to adjust speed, or whatever, but when trooling for blackmouth in the winter or crappy weather in the summer, it is nice to be out of the weather, under cover.
Have fun setting up your boat! Hopefully this helped somewhat.
Andy
P.S. When we feel like it, we still ski out of the boat, and all of the add-ons come off in a matter of seconds.