Unfortunately, I think you may have to, if you already have your chip. I say this because, the info Brian posted said it would trigger the shutter for around 3 seconds, which in many instances is not enough without the refresh. Now, if you don't have your chip yet, I bet Brian would surely be willing to program a longer time so that you wouldn't *have* to.
In my opinion though, I would hook it up if I had the option.
The shutter time is four seconds. If you are using the Owl PF I would also recommend using the refresh since it is built in and only requires one more wire. The optos have been optimized for minimal current drain for the three wire system and will not work for a two wire system with the solder bridge unless you change out the resistor to the opto from 10K to 1K.
The functionality of the refresh guarantees the camera will take a picture as fast as it can and that it will not be waiting on the flash to charge. You will notice that after the delay between pictures it will refresh the camera before enabling the PIC for the next trigger this way if it was in a long delay say 20 minutes or more depending on your settings the refresh would build the flash back up in case it was triggered again right after the long delay.