Roger,

If you do not have a balance, you can just put the same amount on each side.

In the long term you need to get a balancer. The Top Flite magnetic balancer will not do a very job on the 16 and 18" props. It's just not strong enough. They will drop out of the holder.

The Robart High Point would be the best one for those big props.

The big props are almost always out of balance when you get them.

Jim