Have been riding 44x16 in New York/Brooklyn (mostly flat, some bridges, traffic) and as I got more in shape I would like to spin a little less and push a little more, so am thinking to either add a few teeth to my 44 or change the cog to 15 teeth (or add a few teeth to both, etc). I can do the math and will have to guess how much harder I will have to pedal but I was wondering if there are ratios to avoid i.e. that don't work very well, or some other considerations besides skid patches.

In other words, for instance, 44/15 gives a slight increase in development over 44/16 but also a much higher number of skid patches (15 as opposed to 4 for 44/16). So, odd numbers seem better (i.e. 47/16 or 49/16 rather than 48/16) or are there other factors that come into play to negate that, whether these are rational or irrational... (I was referring to the 44/14 ratio - 3.14... and 7 skid patches!)
Thanks.