Decades of observation, starting with a Bolger-designed double-ender I built around age 16, suggest that hulls with narrow, double-ended waterlines are amazingly permissive about sail balance.  It's worth a magazine article at some point.  

Moving the mast aft an inch won't matter a fig.  

You can also fine-tune the lug-rigged Skerry's balance a lot by shifting the downhaul attachment point.  

   When I first contemplated switching to the lug rig I mocked it up with a cheap wood mast and a polysail. OK, it's not the most glamorous but it worked in light and moderate wind.  So, I sailed the boat a couple of times and then I steam-bent about a 5-degree rake in the mast because of the exact issue you mention.  Upshot?  I couldn't tell any difference.

Honestly, I think that where you sit in the boat is going to affect balance more than an inch or two of sail adjustement fore and aft.  I'm really putting some effort into making a comfortable space in the aft half of the boat, but as close to the thwart as possible.