Flashing for carport

I'm building a carport 9m long attached to the side of my brick garage. It will have a 16mm polycarbonate roof and a shallow fall - about 75mm over 3m width. I'm unsure about what flashing to use. I was thinking of using lead or Ubiflex, but will capillary action allow water to get under it? If I use butyl won't it stick to the roofing and cause problems when the polycarb expands/contracts? The roofing suppliers say use Flashband but isn't it messy (bitumen?) and less durable, and same problem with expansion/contraction?
Thanks in advance.

just run a generous bead of lead seal silicone under the leading edge of it and that will stop any driving rain getting up in there.

That sounds good. If I use that sealer then what's the minimum flashing depth I would need over the polycarb, and would it be the same for lead as Ubiflex?

Thanks again for your help.

If you use Ubiflex, you have to stick the leading edge down, so this will stop any capillary action.
If using lead do as 896neo.
Lead or Ubi, 150mm upstand, suggest go out to 225mm on slope, to be on safe side.
old un

OK. Many thanks.