I use medium size spuds that sit within the palm of your hand and cook for about 35mins a side on 180deg.
Before putting them in the oven I peel the spuds then put a knife through the spud in the shape of a "X" but not the "whole" way through. Just enough to where the tip of the knife hits the other side. Then repeat on the other side but a shape like "+".
Coat with rice bran oil, mixed Italian herbs, tiny sprinkle of garlic salt and then normal salt. Cook for 35mins then turn over and re-coat with the oil in the baking tray using a turkey baster. Throw in for another 30-35mins.
I'm using a fan forced oven and it works every time, nice and fluffy inside and a crispy outer casing. Soon as you cut into the spud the steam rises and smell that roast spud smell.
Half cut into 6 sections then litely mash the insides before putting in butter and a dollop of sour cream. If you have made a gravy drizzle some over the top also.