There is no additional restriction on the nationality/passport. If you can get the visa, you get the same terms. SETV is 60 days and can be extended for an additional 30 days at immigration for 1,900 thb. Need to get the visa in advance of arrival
This came into affect a couple years back. They won't give you a multiple entry 1 year Non B at a consulate unless you are a director of the company "which considering your WP says you are not, they are denying you this). You need to get the 90 day Non B and then get an extension of stay inside of Thailand, or get a work permit as the MD and then apply outside again for a 1 year ME non b
3-4 tourist visas, a few multi-entry non-b, then visa exempt, and now SETV. So not a lot of back to back tourist visas over the last few years, but consulate did question me a lot about working when I applied for the tourist visa as they flicked through my passport. Immigration at Phuket didn't care at all.