Using Cast Iron Flange Replacement as "removeable" flange for PVC dwv

Hi and thank you for any feedback. I am building a bathroom with all of the plumbing between the bathroom floor and the slab 8" below. (thank you all for the feedback on my last DVW post - I was squared away and passed inspection no problem.)
I was planning on making some means of opening the floor - in case of a leak etc. I therefore did not want to glue the toilet flange to the closet bend and considered using oatey's "Cast Iron Flange Replacement" in place of a standard flange. This is the one whereby tightening three screws form above a large rubber bushing is compressed such that it grabs the inside of the pipe. It is designed to replace (broken?) flanges in cast iron systems but Oatey's website says that it fits inside 4" PVC DWV as well.
Has anyone any problem with this or is there a better product/way?
thank you
John

IF you have to open the floor for ANY reason, removing and replacing the toilet flange will be the cheapest part of the job no matter how it is attached. Plastic is a lot smoother than cast iron, so I am not sure if you can tighten it enough to prevent it from "working loose".

Thanks!
I shimmed the closet bend so it wouldn't be hanging from the flange. I thought therefor it didn't really need to hold on too tight, just keep anything from escaping. The thought was not the cost, but I figured it would be destructive too pull up the flange if it is glued. I suppose you guys have an inside pipe cutter that makes it simple!
John

It should be fine...as long as you don't mine the sewer gas that will escape through the shimmed joint that is not too tight. Of course if there ever is a clogged drain, your not too tight joint will allow sewage to pass through as well. Guess if that's good enough for you, who are we to be critical.

I think by shimmed we are talking about different things -I simply meant I put some material under the closet bend such that it is very well supported by the slab below. Therefore the closet bend and some of the downhill pipe is not using the floor, on which the flange is screwed, for its primary support. I was responding to hj's suggestion that the gasket used by these "cast iron replacement"flanges to grab on to the pipe is not going to hold as tight to PVC as it would to cast iron and suggested it could "work loose."