Screws for bleed vent TRF 501X dampers?

[kaszal]

I'd like to get the "54028 TRF buggy aeration damper set" and wanted to know what size screws you need to use the bleed vent. I read Jimmy's review and it says 2mm screw. I can get these off ebay but what length e.g. M2 x 5 ? Does it matter if they're grub screw or flat head? Also wondering where's the best place to buy e.g. eBay or can you recommend a Tamiya dealer? Thanks