To get a 100m roll from EC you just enter 100 into the quantity box. Works out at 32 pounds per metre.
Those fabrics would
probably be fine. The thing that would put me off is the lack of actual technical data. That first one is alright, it says it is twill or plain weave (which is what is pictured), but the second one lists all these weave types and doesn't have one of them pictured. Which is probably fine, I imagine they are offering those weaves and make them to order, I just think that if you are selling a product you should have a picture of it. Also further down the page they only list their available plain weave fabrics, which I find a bit odd.
The other thing is weight. The first one is 200gsm, which is fine for your bonnet if you do a few layers with a core. If you're doing only fabric, I would prefer to have a heavier fabric in the middle, otherwise you're gonna need to do quite a few layers of just the 200g, which is a bit of a waste. The second one lists a 200g as well, but it's all plain weave. So you'd need to decide what weave type you require.
And lastly, you're taking a chance that it's a high quality carbon fibre. If you were doing cosmetic parts only then I'd say go for it. But if you're doing structural body panels, I would want to know that the fabrics are made using high quality fibres. You could try contacting the supplier to find out if they can tell you.
TL;DR: Linked fabrics would probably work fine for what you want, but you are taking a bit of a risk, especially purchasing such a large quantity.