They no longer make the pro-survival belt kit and i can't find (in England) a belt with an innner zip pouch all the way along the length to make my own. So Dougs pocket size one (plus torch knife etc)in a belt would be good.
And I second the vote for something between the pocket kit and the 2 man plane one. A solo backpackers size one.
Simon
I think a CamelBak size PSK is the right size while hiking or for your car/4x4 if you have to walk out. Plus, you have the main survival item: water.