Filter setups for lenses with large center filters

[newmoon2night]

I realise that this thread is 6 months old, but I have the same questions with 112mm filters, specifically for a 72mm lens.
I have a Lee standard 100mm system, and also have a Cokin X Pro holder and a couple of filters.
But I really don't like carrying around two systems, and the Cokin system is a bit big!
I just noticed on B&H that there is a 112mm adapter ring for the Lee system (it's not listed in the Lee catalogue) http://www.bhphotovideo.com/c/produc...ing_112mm.html
By any chance has anyone tried the Lee 100mm system with a 112mm adapter, fitted to the Schneider 72mm lens and centre filter?
Is it almost a certainty to vignette - even without movements (the depth of field at f/32 with this lens, and the difficulty in seeing edges clearly through the ground glass mean that I don't really use movements with this lens)?
I am waiting for a shot I took with a Lee filter hand held in front of the centre filter to come back from the processors, so I'll know part of the answer, but this won't take account of the depth of the Lee holder.
Does anyone have any experience with this?
The alternative for me is to standardise on the Coking X Pro size.
Thanks.

[percepts]

What do you suppose the thread on the rear lens element is for? Maybe not a grad but most other filters can go there.

[newmoon2night]

What do you suppose the thread on the rear lens element is for? Maybe not a grad but most other filters can go there.

As far as I can see the 72mm lens doesn't have a rear filter thread, though I agree it would be an option in other cases.
Looking at the Schneider lens chart, I don't think any Schneider lens below 110mm has a rear filter thread (though the 110mm lens does have one).