Roast potatoes IV suggested parboiling the potatoes, draining them and allowing them to dry, and turning them in oil before roasting. The theory was that they crisped just as well this way as they would have done when added to hot oil; and this method was easier. I had always found turning the potatoes in hot oil in the roasting tin a bit of a nuisance.
But what if you don't need to give them an initial turning? Browsing on Video Jug when I should have been at work, I came across its roast potatoes recipe. You start as usual by parboiling the potatoes; the recipe advises draining them by tipping the pan with the lid partially ajar, but there is no good reason why you should not use a colander. Meanwhile, you warm some fat in a roasting tin. Then you simply lay the potatoes in the hot fat -- no turning. The Video Jug demonstrator adds his potatoes one by one; I am prepared to risk splashing by tipping them all into the tin at once. You turn the potatoes half way through cooking as normal.
The advantage of this method is that the potatoes form a crust quickly, and therefore absorb less fat. You need not worry about giving every surface an initial coating to get a crisp and tasty result.
I have been slicing my potatoes for roasting rather than cutting them into chunks. They work well.