RAM block type mixing/balancing

I believe that works when you have many RAMs, i.e. moving some from M9Ks to MLAB RAMs, maybe moving an M144K to M9Ks or vice-versa. But I'm pretty sure it moves each logical RAM to be 100% of one type or another, so when the issue is a single large RAM, it doesn't apply. (There was a time where the fitter might target all M4Ks in Stratix II, for example, as that was the best fit per RAM, but as a whole it would run out, when there were plenty of M512s available.)