what you think of this carb?

30mm would be a great size to suit your mods, but I would be wary of any cheap carbs, especially those from a comparitivly unknown maker.
 
i run a 34mm pj from a trx250r with very similar mods to you and same pipe, runs great, but there are better/easier to tune carbs out there,
i'd jump on a 33mm pwk airstriker if i could find one for a good price.
pwk 28mm's from the yz/rm 85cc jap bikes would be a good choice too pricewise, i see them for around $60-80 on ebay