Opinion: Small motors more or less consistent than big motors?

The carb is the biggest thing that is effected by the weather.

Running the carb on the lean side will make the car more consistent.
A carb that runs on the rich side, tends to slow down the car as the air temp increases and pick up to much(faster et) as the temp decreases.
Leaner is way better.

Larger cubic inch engines make the carb work more efficiently.