The dangers of sponsorship

Over the last 6 months or so a friend and I have grown into a 'co-sponsorship' relationship.  He had decided to go through the Steps again and wanted a fresh perspective on them and I need someone to slap me around a little when I let unemployment get me depressed.  It's funny, because we both have sponsors, but this sort of arrangement on these particular issues just seems to work.
This morning I sent my friend some comments on his working of the 3rd Step and it got me thinking about just how careful we have to be when sponsoring.
 It goes without saying that the sponsor can only guide or comment based on his understanding of the program and his spiritual state.  The obvious risk is imposing the sponsor's spiritual path on the sponsee.  I don't think it's enough to say 'just strictly follow the guidelines in the Big Book and 12 and 12'.  First of all, the Big Book leaves a lot of room for interpretation.  A quick look at the differences between the various 12 Step guidebooks or listening to a sampling of AA recordings will convince one of that.  Nevertheless, attempting to follow the BB as strictly as possible is appropriate for a first time through the Steps and is often the correct approach for a 'refresher course.'  However, as one advances on his or her spiritual path, 'customization' can become appropriate, precisely because it is his or her spiritual path and not some generic highway.  Concretely, in my comments on my friend's 3rd Step I suggested focusing on applying the results of his 3rd when doing his 4th.  In defining his Higher Power(s) he has determined values he wants to turn his intentions (will) and actions (life) over to.  Following the comments on page 68 of the BB I'm asking if he wants to evaluate his resentments, fears, etc in light of those values, focusing on evaluating how well or poorly he has allowed himself to be guided by his Higher Power.  This is not something I would try on a newcomer, but something I think could be appropriate for this long-sober guy.
Now, of course, this suggestion is based on my understanding of the Steps and on my experiences on the spiritual path of AA.  That's what scares the crap out of me.  It reinforces my conviction that sponsor and sponsee must view themselves more as fellow pilgrims on the path rather than as master and apprentice.  The sponsor must carefully listen to the sponsee and the sponsee must push back and test the sponsor's mettle.