biggest impact on the ability of a rider to keep its edge
?
The boots, actually, I think
Copying the cab might be the best case rather than the worst case.
Skip the channels (they're a PITA, trust me).
You won't get the rocker exactly the same, or the flex, but at least rocker and outline will be in the right neighborhood.
What comes out different, you may like better (hopefully).
If you are going to use boots for sure, make it a little longer than the cab you have. For the outline template, I would make the % enlargement in the long direction a hair more than in the width direction, but be careful not to make it too parallel-railed or carving may suffer unless its a noodle.
A tasty recipe imho for a 75-85kg rider (boots +/-) would be:
138x42, concave 5mm in middle, flat tips.
deck 650gsm e-glass
extra 100-200 patches around inserts
wood core (9-10mm if cedar or poplar, 11-14mm if paulownia or balsa, tapering to 2.5-3.5mm at tips)
bottom 450gsm e-glass, with extra 100-200 between inserts.
If you use cedar, poplar, spruce, larch etc.:
Preserve your rocker: Leave the board on the rocker table a few days to let the resin completely harden.
Preserve your rocker: Leave the board on the rocker table a few days to let the resin completely harden.
Preserve your rocker: Leave the board on the rocker table a few days to let the resin completely harden.
That was not a typo.
Have a method of clamping the board onto the table other than vacuum to facilitate this (search past posts, or think sand, weights, screws etc.).
Ride the board before putting any fancy finish or graphics on.
If board is too stiff, carefully grind into the top deck layer with orbital sander until you are "1/3" into the glass. Re-fill and reassess. Repeat if neccessary.
If board too limp, grind up a viagra and mix with shellac, apply to your face --oops, I mean add another layer of glass to the deck.
When satisfied, decorate if desired.
Have fun.
Re: other issues you mention, use larger fins (35-50mm) in chop/harsh conditions to help with control, boosts and avoid side-skipping, less or no fins in flat water to butter it up etc.
Concave helps set an edge and stay in control especially at the newb level, with boots it is less neccessary.