All good answers for you to ponder ncage, I cook fish and chips for a living. Here's a photo of a tray of chips par-cooked, ready to finnish off.
I cut them 1" x 1/2" and lightly batter them first.
I think that it is up to the individual as to what sort of batter to use, I've given up on making my own so use a commercial one for convenience. Beer batter is popular, plain soda water, lots of different ways to do it and each person seems to make it a bit different. Flour is important, above 10% energy is good.
My cooking temp for battered fish is 190c and 180c for chips
By lightly battering the chips they will not shrink and hold at their origional size and shape thus making them much lighter inside.
For us we have no choice but to use Sebago potatoes which are fine, but, you much watch that sugar content, to much sugar and they will go very dark [the sugar burns] on the second
cook before they are cooked through.
Enjoy your F&C's, great food