I'm installing a Ideal Standard 'Space' back-to-wall' wc. A high level
concealed cistern sits within a boxed-out wall, which will also contain a
stub stack, directly behind the wc.

If I measure everything correctly: height etc. is there anything to stop me
connecting the porcelain horizontal outlet of the pan, directly into a
branch connection on the stub stack. I'm using hepworth stack plastic
drainage with rubber ring seal which fits nice and snug over the outlet from
the pan.

I know you often use a wc connector, which might be straight or elbowed in
some way and has more rubber fins in the seal, but using a straight
connector in line will increase the distance between the wc pan and the
stack, defeating the whole purpose of using a space-saving wc arrangement.

I don't want this to leak for obvious reasons.

Thanks once again.

KB, Oxford