Clean out question

[DIYluke]

I would like to add a clean out wye to a horizontal wet vent under my bathroom floor. I would access it in the adjacent closet.
I have learned from this site that no horizontal dry vent may be below the point 6" above the flood level of the fixture. I have also learned this wouldn't apply to a wet vent.
My question is this: to get the clean out wye in the wet vent run and be able to access it I would need to run a 24"+/- length of pipe horizontal under the flood level of the fixture (under the floor) to the clean out adapter. It wouldn't be dead horizontal, but only 1/4" per foot. Would this be allowed due to the fact that it's neither a wet or dry vent. More like a clean out branch (if that is a thing)?

 

[Terry]

Adding the horizontal piping to add a cleanout works.

 

[Sponsor]

 

[DIYluke]

Thanks for the info.