Nic, an offset of +45 with JJ of 11, is pretty much equivelant to an off set of +32 with JJ of 10 and the guys here with the Wed's wheels pretty much have the above offset and only encounter rubbing when running 285's on the 10jj's which can easily be resolved with a little bit of arch rolling:)
So the above 20" wheels will only rub if he goes for tyre's bigger than 285's on the 11's (285's are the actual reccomended size for 11jj's). This is also dependent on the brand of tyre.
When choosing my Racing Hart CR's I went for very low offset's to get a much wider stance look, I compared them to Wed's and all sorts just to get the right offsets etc.
So bascially, If you want those wheels in those offset's, they will fit aslong as you choose the right tyre, You'll have a stretched fitment look with the 285's just like in the picture you posted, again this is dependant on trye brand.
Id personally go no larger than 19's bud.