Just north of Chicago, I’m installing a Gerberit wall hung toilet in my home’s new addition. The 3″ line below the floor drops vertically approx 19 inches before I  need to go horizontal, which leaves me enough room to T a 2″ vent line and below that T the 2″ shower drain before the long sweep combo.  I get that I will need to dry vent due to the vertical pipe (I think) but reading on the internet makes me think the wall hung unit works best if you don’t try to go horizontal right away. But I also recall reading on a European site that it is recommended to install the vent as far away as code allows to assist in the siphoning/flush of a toilet. I think code allows moving the vent up to 6′ away. Would it be better to move it? And if I move the vent downstream to the top of the horizontal line, wouldn’t the flushing of the toilet siphon the shower trap?