Big Boy wheels are the way to go.
The standard wheels can easily get caught under the bullnose on steps.
My
Bigger Wheels 
are different in that they are indeed larger than Rick's Big Wheel Kit, (10"), also mine are pneumatic, (
pump-ups for those down south ).
Some say mine are too big, whatever floats your boat, they are ideal for me.
This makes them ( for me ), easier to take up & down stairs when I have to, as the air acts as a shock absorber for both Big Yella & I.
The stock/standard wheels are hard, Big Wheels are semi pneumatic, like the wheels on a dehumidifier if you like.
This will give you an idea, mine are 12 & 1/4" .
