Tom, we had a similar situation with #23.  We decided to do immediate provisionalization.  Here's the beauty of Ankylos.  The emergence profile of the crown is INDEPENDENT of the size of the implant.  Originally, the periodontist (Bill Cohen) wanted to use a 3.5mm implant but could not get adequate primary stability..think of the shape of the lateral root.  He then decided on a 4.5.
The second PA is of the provisional in the mouth at 4 months.  Look at the clinical pictures of the provisional and the tissue once the provisional is removed.  
Despite the closeness of the implant to the adjacent roots, there is still plenty of inter-restorative space because the narrowness of the Standard abutment has nothing to do with the size of the implant.
This was just taken two days ago so no final crown yet.
I'm sure you'll have a great response in your patient.  
Barry