To answer your question and not ridicule your wording, your bow manufacturer sets a minimum arrow weight to 5grains of arrow weight for every pound of draw weight
This is a good rule of thumb.....but High Country is warrantying their bows for a lot less (3#'s?). I'd still stick with 5 for a hunting set-up (my preference) and go UP from there....based on your arrow speed.
Do you have access to a local bowhsop? They should have a chrono you can shoot through and a digital scale (to measure the weight of your arrows). In the absence of a digital scale.....you can look up the various components that make up your arrow, online, and come up with a guesstimate on total arrow weight.
That's all you need. Arrow weight (total) and arrow speed to figure KE.