@Cabra *********
, well you have plenty of time on your current stamp. There's no reason you couldn't go on the 8th and apply for the Non-O visa in section C-1 at Chaengwattana.
OR
Take the 30 day regular extension if you want to (the 30 days will be added to your current expiration) and do it when that stamp runs down.
Either way it will work out fine. No issues at all applying from a 30 day extension as it ties back to your original entry stamp.