First of all, i use a motorbike cargo net on my deck 6euro/dollar which is excellent and nothing gets through it. it can carry anything and everything. its threaded tightly in through my deck elastics and deck lines. i have seen the carrier systems by for instance sealine but these involve zips and ratchets and dont have that 'shove in and forget about' quality about them, too finicky in a big sea.
regards knee tubes, i evo stuck a quantity of plastic watertight containers between knees and outside hips/seat. these too work well after i had fixed their lids with small shock cords. very cheap also and adjustable. i think knee tubes will have it on watertightness though but be aware that they do affect the secondary stability of the boat if too packed.
some good sea pfd have plenty of pockets but these should be taken up with safety devices ie knife, whistle mirror, flares etc.
just dont pack the back of your pfd too much as this can impede your roll.
the day hatch behind your right buttock accesses through the deck is quite popular but requires rafting up to access in all but the calmest weather
hope this helps

Seeking the advice and solutions from those who've been paddling longer than
: I (about a year,) on stowing and carrying assorted small items (water,
: food, binocs, camera, knife, bug stuff, sunblock, etc..)

: I'll soon be building my first boat (Nick's S&G Night Heron). All of my
: paddling to date has been in other folks boats -- borrowed, rented, on
: tour, etc -- so this will be the first boat that I am outfitting myself.
: Most of my paddling is day trips, and in the South Carolina Low Country,
: much of it is in hot weather.

: I'm thinking about outfitting the boat at the same time as I am making other
: purchases -- PDF, semi-drytop -- and I find I am thinking a lot about
: where to stow these little items. I've always been willing to make due in
: the various boats I've been in -- sometimes needing to open my skirt to
: access stuff... from time to time losing something from under and
: inadequate bungies... But it seems that with a little thought I can
: eliminate most of those hassles.

: I'm just wondering, between knee tubes and day hatches, pockets and deck
: nets, hydration packs and bladders -- what solutions are you folks
: happiest with? Anything I don't see on commercial baots? Anything novel?

: A good paddle park is about the only thing I am sure I am planning on at this
: point (hook and bungie).

: Thanks in advance,
: -Steve