How to rough this wall hung toilet in attic?

[JoninNYC]

I'm replacing an old wall hung toilet in the attic from the 90's. Previous owner cut out a metal plate and used that as the carrier. I'm installing the Geberit carrier and the problem I am running into is how to connect the waste pipe. Instead of going straight down, the waste pipe is actually set back in the alcove of the attic.

Previous toilet used 2 wyes (see photo). Is that code? Could I do the same with PVC on this new carrier?

Or I could see if Geberit has a waste pipe that just goes straight back instead of down? Then I can do the a sanitary tee to a sweep to the wye?

Thanks