Not sure if you can retrofit other outfitting into a jackson, if you did that it might require doing some hull drilling. Of all the boats out there the jackson boats will be the most difficult to retrofit due to the fact that the way they install outfitting is so different from any other kayak manufacturer. If you try make sure that you really measure the outfitting that you want to install and be sure that it will even fit before drilling your hull.

I'd say your best bet would be to just go old school, buy a bunch of foam, a couple different types of rasps, some rubber cement, sandpaper, and get to shaping some foam. It's a bit of an involved process that involves some trial an error, but once you have it dialed it'll work better than any factory designed junk out there.

Most factory outfitting is designed to fit the "average boater", but for real small people, real tall people, or big folks, the factory gear doesn't work well.

If your looking for foam shaping advice I'd cruise the www.Cboats.net site (similar to Professorpaddle), and I'd also try the Angst squirt kayak message board (http://www.angstkayak.com/messageboard/index.html), it's not as user friendly as PP but squirt kayakers are master foam shapers. If you try to post on cboats.net, but be careful not to make mention that you'd be outfitting a kayak, they're pretty territorial about keeping it a cboat related only site, or maybe post in the "Off Topic" forum.

Good luck, wish I had a more silver bullet answer.

Another thing to factor in is that some boats tend to break where the outfitting is bolted in. This is probably a bigger problem with bigger people than smaller people, but... We're talking about breakage in boats that were engineered to have these pieces bolted in. It's been a big problem for manufacturers over the years. Drilling holes and bolting in pieces all willy nilly could be asking for big problems.

I know you don't want to hear about minicel(which ROCKS) but here's couple little things...

Not all minicel is created equal. Most of the foam we use to outfit our boats is made from the softer, mushier minicel, while the center pillars are made of a much stiffer type of minicel. This stiffer minicel may be what you're looking for, if you don't like the normal mushiness of normal minicel outfitting. See http://www.sweetcomposites.com/Minicel.html These guys have lots of cool stuff. Look around a little. It was founded by John Sweet or Sweets Falls fame(Gauley River in WV) and he sold it to the Hearn's a few years ago. As is mentioned on their website, the shipping for minicell is pricey. It helps to get a few people together and buy it in larger quantities. This, assuming you can't salvage foam from a broken boat.

I usually ditch the thigh braces in my boats in favor of minicel and I've helped others set their boat up as well. On the last boat, I took pictures. <table style="width:194px;"><tr><td align="center" style="height:194px;background:url(https://picasaweb.google.com/s/c/transparent_album_background.gif) no-repeat left"><a href="https://picasaweb.google.com/110924113960435508796/OutfittingThighBraces?feat=embedwebsite"><img src="https://lh4.googleusercontent.com/_8iRXv7xUd0w/TNS7EaPj6LE/AAAAAAAAE6I/RPBt76l9MME/s160-c/OutfittingThighBraces.jpg" width="160" height="160" style="margin:1px 0 0 4px;"></a></td></tr><tr><td style="text-align:center;font-family:arial,sans-serif;font-size:11px"><a href="https://picasaweb.google.com/110924113960435508796/OutfittingThighBraces?feat=embedwebsite" style="color:#4D4D4D;font-weight:bold;text-decoration:none;">Outfitting Thigh Braces</a></td></tr></table>

Note: Not all "closed cell" foams are suitable for outfitting. There is a reason that minicel is the only foam used. This is not the same material as foam bed pads, pool floats, beer cozies, etc... All that stuff will absorb water as time goes by, allowing even nastier stuff to grow in our boats than what usually gets trapped under our seats, bulkheads, ect... Not only will this foam get filled with water, it will not dry out as easily. This extra water will make your boat heavy. I've bought several boats that lost nearly 10 lbs after I stripped out all the non minicel outfitting. These other types of foam are not as easy to work with either. They won't shave and shape as easy as minicel. Also, most closed cell foam tends to have their cells damaged when crushed(which explains why they get full of water) which means that the foam will shrink quickly. In other words, when it gets crushed, it never comes quite back into shape. Minicel is much, much less prone to this crushing, though it will eventually "shrink" from getting crushed, though it will never absorb water, even after worn and crushed beyond recognition.

Dammit!!!

https://picasaweb.google.com/110924113960435508796/OutfittingThighBraces?feat=directlink