Jumbo Oats in an Oatmeal Stout?

[Wobbler]

Thinking of trying an oatmeal stout today.

I couldn't get flaked oats where I get my grains from, but was told to get jumbo oats instead. I forgot to ask if they needed cooking or soaking first, so does anyone know if I need to do anything other than mix them in with the rest of the grist?

TIA

[Wobbler]

Ok cheers.
If no-one else chips in, I'll cook them up first as you suggest. I've got a few hours before the water goes on.

I can see myself struggling with working out the quantity of water for the rest of the grains. The pack of jumbo oats says 300ml water per 50g, then I need a bit extra as well. If I'm using about 700g of jumbo oats I'll be looking at approx a gallon of water.
Oh no, I haven't got a pan big enough, got several small ones though.

[Wobbler]

In the end I went for less jumbo oats and added some carapils malt to the recipe. Used 400g of jumbo oats, divided it up into two pans and put 1.5 litres of water in each. I then worked out the total grain, x 2.5 litres mash water per kg, minus the 3 litres I used with the oats. So basically the same as you just suggested, by counting the oat slop as mash water, but the words "big dollop of water" never even entered me head.

<edit>
........now only 30 mins left to mash. Soon to be a squeaking.

[Wobbler]

Nope, got 5 gal treated water sitting there at about 78°c.