Flexible Pan Connector

[MortarThePoint]

I am having a 'back to wall' toilet which is going up against a box-in that contains the concealed cistern (~100mm deep). Behind the cistern is a blockwork wall through which I will be passing the 110mm soil pipe. I think this will leave about 125mm between the back of the pan (and its spigot) and the blockwork. A flexible connector like the one below feels like a good option to connect the pan to the soil pipe if the soil pipe extends only a little way past the surface of the blockwork.. As I haven't tiled the floor yet, I can't be sure of the exact height, but should be able to get the soil pipe to within about 10mm of where it should be.

 

How much vertical offset could a flexible pan connector like this afford me? I'm wondering if I should drill the hole in the blockwork oversized (127mm instead of 117mm) just in case.

https://www.screwfix.com/p/mcalpine-flexible-straight-wc-pan-connector-white-100-160mm/6458P

https://mcalpineplumbing.com/wc-connectors/flexible-wc-connectors/wc-f26rc-straight-flexible-wc-connector

[Temp]

Does the pipe have to go straight through the wall? Sometimes a dog leg just makes life easier.

 

Flexible connectors have/had a bit of a bad reputation.

Edited September 5, 2023 by Temp

[Crunchynut]

I would certainly drill the hole oversized. Chances are you will need it.
 

Too many times I have gone for precision which was precisely not quite right, but then to find that making  an adjustment is really hard if not impossible. 

[joe90]

I too went to great lengths to measure accurately where soil pipes should go, and found it was not quiet right, I bought numerous pan connectors (they can all be different by small amounts) so I would definitely drill oversize and give yourself wriggle room.

[MortarThePoint]

I drilled an oversized hole to allow a bit of wiggle and will pack it with acoustic roll when done. Flexible / offset pan connectors could give me extra wiggle room too.