Quite frankly most any currently available yoyo is unresponsive with a clean bearing. The condition of the bearing is the prime ingredient in responsive/unresponsive play.
I ordered mine not on here because I also wanted some highlights and clear fhz so maybe the other site added one in. It would make sense because it wasn’t shielded. Anyways, yes you can use it for 1a.
My half spec came deshielded. I can’t speak for YYJ’s slim bearings but it seems reasonable to generalize that slim bearings would usually come deshielded because of limited space. It does seem interesting to me, though, that a yo-yo primarily designed for offstring would be designed with such a large gap. I’m truly curious to know who got the odd one out - Cameron or cbaxt. I personally think it would only make sense to include a slim bearing with it - especially if they are already doing this on yo-yos designed specifically for 1A which is generally played with a larger gap width, but that’s just me.
I read somewhere else that YYJ shipped them with the wrong bearing installed and that website would ship the slim bearings to all their customers that ordered it.