There are a lot of factors (speed, current, weight of lure, weight of line) etc.
It would help if you could mount a GPS on the yak to get your true speed. The other question is what are you fishing with and what is your target depth? Are you trying for 10 feet down or 40 down?
There are a lot of charts out there like this... http://www.daybreakfishing.com/LureDepth.html
I doubt you will be pulling U-rigs on tha yak, so we can rule that one out.
The other thing would be lead core line and lead core line charts. Normally here we use lead code @ 2-3 mph, you will be doing a lot less and should look at some of the speed/depth charts for salmon which normally are fished a lot slower.
Here is a nice chart for lead core.
For me, my kayak fishing is limited to winter on the lake and typically the stripers are in the 1st 10' of water so I just use a swimbait with 1/2 oz or deepdriver.
Good luck, there is nothing more fun than hooking into a striper on a kayak.