If you are just starting out reloading, especially if you are using a single stage press, then use a powder like Trailboss. This is a special extra bulky powder, made for light loads.
There is far less chance of a mistake by throwing a double charge. Fast burning powders like bullseye take up so little space in a 38 case that it is hard to see if you have double charged the case.
After the first pound of powder, you will have gotten into a rythem and are aware of what to look for, then use the fast burning, low volume powders.
K