Your Sekonic L-508 you should be able determine the proper exposure from you monolight....
You'll need to take separate readings for the ambient light and strobe to determine your f-stop setting (since you'll probably be trying to sync the flash at your camera's highest shutter speed setting).
If you are just using the built in reflector, 160 watt/sec is probably fine at relatively close range - say 15'at f4 set and 100 ISO. However, at f4 you'll need to shoot in the shade, or at twilight.
Assuming my f4 at 100 ISO guess is correct, and you are trying to balance full daylight, you'll probably be about 3 stops or about 500 watt/sec short of what you'll need because you'll need f11 with a shutter speed of 1/200th or 1/250th /sec.
BTW - If you plan on shooting with a umbrella or softbox, you'll need to make up for several more lost stops due to the light modifiers.
Anyway, I suggest getting a long extension cord or just renting the equipment you need for the day.
Aloha from Hawaii,