Hunting humble apple crumble

I don't normally use a recipe for apple crumble, I just guess. But wanting to make a really good one for a weekend visitor, I decided to hunt for guidance on the web.
      As you might expect, apple crumble must be one of the most-posted NZ recipes. What surprised me was how different they all are - not just in ingredients, but in quantities, methods, oven times and temperatures.
       I was struck by how many commercial recipe sites there are, often trying to sound like a real person, and all touting for business. I was shocked - shocked, I say! - to see the New Zealand Women's Weekly featuring a "Classic Apple Crumble", using cans of diced apples. (I expect this kind of heresy from Wattie's Food in a Minute, and sure enough, it had canned apples too, plus jam.) Saving time? Not really - it also says to rub the butter in by hand, when it's much quicker to do it (by careful pulses) in a food processor. I haven't tried melting the butter and stirring it in, as some recipes say - would this work? I'm doubtful.
        The Woolworths recipe uses fresh apples, but tells you to cook them first. So does Jamie Oliver (the only non-NZ recipe I looked at). I thought the whole point was to put fresh sliced apples (maybe with other fruit) under the topping, then cook the whole thing slowly in the oven along with something else that takes a while, like a casserole.
        Oven times and temperatures are another bone of contention. Lots of recipes with precooked apples, or even sometimes with sliced ones, say 20 minutes at 180C, and that's just not long enough. My old Easy As Pie textbook says not to have the oven too hot, or the fruit "will bubble up and spoil the topping" - but Harvey says that's exactly what he wants it to do.
          He's a stickler for tradition - he likes his topping thick, and made with white flour only. Others are more adventurous. As well as the basic butter, sugar (choose your kind) and flour (white or wholemeal, with or without a little baking powder), toppings can include a little or a lot of rolled oats, coconut, ground almonds, and/or spices. The amount of butter varies from skimpy (producing dull, stodgy topping, in my experience) to generous.

Very few recipes give the number of servings. Jamie says his serves 5, but the whole raw topping weighs only 125g - barely a quarter of a cup each, which does seem a bit sparse.
         In the end I went for a Cuisine recipe, because it used fresh, not precooked apples and had a unique variation I wanted to try: mixing the rolled oats with honey and half the butter, melted, then baking them for 20 minutes spread out on a tray lined with baking paper, before mixing them with the butter/flour, sugar, and cinnamon, and cooking for 50 minutes at 180C.
         It tasted good, with a nice toasty flavour, but because the apples weren't proper cooking ones (like Ballarat), I think they needed to cook a bit longer (with foil over the top to stop it getting too brown). And despite its name, we like our crumble a bit less crumbly and more sort of solid. Fewer rolled oats, more flour, maybe more butter.
           If you have a favourite apple crumble recipe you love and swear by, let me know. But please, no canned apples.