I think you may be taking some of what's in the Guy Cribb articles kind of "out of context".
Look at the board he's riding..... it's a small narrow wave board and I'll bet it has a fin < 30 cm under the tail.
I agree with Guy that to get upwind on this type of board, you need to use the upwind rail. (banking the board).
To apply this to "ALL" kinds of boards is just plain wrong.
Look at formula racers and almost anyone on a board wider than 70 cm with a fin larger than 50 cm.
Tipping the board upwind rail down is very inefficient when you have a big pointer foil under your board.
Then you need to tip the board slightly lee rail down and push hard on the fin while pulling up and out a bit with your front foot to control the roll attitude of the board at an angle that will give you the best horizontal "lift" upwind.
Guy's comments about feathering the rig are right on, regardless of what board you are on.
As far as standing up straighter and putting more down pressure (vs side pressure) on the fin, it depends again on the board width and fin size.
So, Guy Cribb is correct, if you are sailing a soft railed wave or freeride board with a smaller fin and smaller rigs.
His comment to bring the rig up slightly (from fully raked back and gap closed) will make almost any board a little easier to sail.
I'm pretty sure that when he says to bring the sail forward, he's talking only a few degrees at most and when he says bring it upwind, he's actually talking about raking the mast upwind, not forward of the mast base.
If you rake the rig upwind, you diminish it's overall size and efficiency slightly and you get a bit more vertical lift from the rig which helps support your body weight.
I think our formula racer friends will agree that unraking your rig will actually turn you off the wind slightly, not upwind, but again they are using an entirely different set of dynamics than Guy on his small finned, soft railed, wave/freestyle/freeride boards.
Hope this helps,