Through draughts will produce the most rapid rates of change of air in the garage/shed/workhop. If there are any through draughts, preventing those will produce the greatest benefit.
If the air leaks in the garage are mostly around the doors, without any through draughts, then reducing the surface area of the gaps, by whatever means, will tend to reduce the rate of air exchange between inside and outside. Adding a bit of heat, and raising the air temperature in the garage by as little as 1 or 2 degrees, can make a substantial difference to the amount of condensation on machinery.
If the air leaks in the garage are mostly around the doors, without any through draughts, then reducing the surface area of the gaps, by whatever means, will tend to reduce the rate of air exchange between inside and outside. Adding a bit of heat, and raising the air temperature in the garage by as little as 1 or 2 degrees, can make a substantial difference to the amount of condensation on machinery.