"Low alcohol content" is a relative preference. German wines are frequently at 10% or so, while most Italian and French reds are typically 12-13%, roughly speaking. Your warmer growing regions like California, Spain and Australia can yield wines with 14-15%. So, 11.5% is maybe slightly on the low end of the spectrum, but a given wine with 10% alcohol vs. 15% will not be good at both levels, almost certainly - the varietal or blend will almost always lend itself to a given alcohol level as optimal. What that is depends on a number of factors, but primarily your tastes. If you like high alcohol wines, then you could add some sugar to the must when you start, but I wouldn't.