Keep in mind that feeding and social habits are far different in the spring than in the fall. What you see now may be nonnexistent or far better after the snow melts and breeding begins. If you have decent private land to hunt with minimal pressure, i would go for the longer, more flexible season. I hunt public land and tend to try for the earlier seasons, as hunting pressure can quickly kill the hunting. As mentioned above, weather has a huge affect on the birds, and a week long season can be ruined in a hurry. May hunting is just as good as late april if the birds aren't disturbed. sometimes, the toms can respond better, as many hens are already on nests, and the gobblers are desperate for a little more lovin'.
I prefer a crow call, though i do hear gobbling to actual owl hoots too. they will gobble at just about every loud noise. several times i have had real crows respond to my crow call, which gets the gobbling going without any more effort on my part.
I would recommend scouting late mornings in early arpil with a crow call. find where you get the best responses and then keep an ear on them without getting too close. the week before your hunt (and especially the night before if possible) find where they roost and set up on them in the dark the morning of your opener.
turkeys aren't dumb and learn from only one run in with a threat of predation. they have the vision of a hawk (see in color too) but cannot smell and seem to ignore, of not respond to noise with curiosity.
if you aren't getting the gobbler in close enough try a tom or jake decoy with a hen. that will piss them off, and i have gotten excellent footage of them attacking decoys before hitting the dirt!
for a little more challenge go after them with archery equipment!