"Preview?" only if if you use decent modeling lights
I looked at the flash duration specs for your light. At full power they claim '1/800" and at minimum power "1/1800" . since they do not specify whether the FD measurement standard used was either t0.5 or t0.1, I assume they are using t0.5.
What is the difference given that they both measure flash flash duration?
t0.5 measures FD when the light output is equal or greater than 50% of the maximum amount of light for the energy (w-s) setting. that is fine for general work but if you need to know how well the flash will freeze motion you need to know the t0.1 measurement - the period that the light output is equal or greater than 10% of the maximum amount of light for the energy (w-s) setting - which is by ISO standards, the full amount of time the flash is emitting photographically relevant light.
If they don't state the t0.1 period is there a way to calculate it?
The rule of thumb for non-IGBT technology flashes is that if you only know the t0.5 time multiply it by 3.
In your case, a t0.5 of 1/800 to 1/1,800 means the t0.1 times are to get a t0.1 range of 1/266 to 1/600th.
In the sub $500.00 price range the better option is a Paul C. Buff Einstein E640.The specs are here:
http://www.paulcbuff.com/e640.php I've been using them for portrait, advertising and industrial work for several years and they have proven themselves to be rock solid.
here's an example of the Einstein's motion stopping capabilities
