[oh'mike]

Add some dimensions to the drawing---what you have drawn will work fine ,however one fewer vent will probably work,too.

 

[oh'mike]

Your set up is fine---one extra vent will only cost you $3.00 or so in parts---I would rather to much than to little---you are good.---Mike----

 

[oh'mike]

I'd raise it ---more for saving your wifes back than the drainage---although the extra height would be a safety margin.