I don't have a memory chart handy. You can go to pana tm90 website and look up card recording times for various quality levels. But remember you also have 16g of built in memory.
As far as brand of card, any top name will do. Just read reviews.
The #2 hot shoe adaptor will work fine. Amazon also has them in the USA.
The zoom s really sensitive. What are you recording, in what type pf area, and how far away will you be? Do you plan to record straight to zoom, then dub sound later, or plug zoom into mic input on tm90?