Speaking on general basis, I don't think it is wise to have them both on the same team, especially not as dedicated special walls. Too overlapping in my opinion, not to mention their typing. Note that Chansey can use aromatherapy to help against poison if you want that (and so can clefable, if you want a physical wall as well) ;) If you want to use both however, I think Snorlax should be like bulky offensive (Curse?), so they don't overlap too much :)
EDIT: The PGL has finally updated! Link:
http://3ds.pokemon-gl.com/information/286edbb3-6e8d-4ade-90f7-86896a7ce102
Yea I was thinking in general. Ooh that would be good. Clefable... that would be interesting. I'll have to see what I have. It's been awhile. Thanks for the tip about Curse.