Do you shoot with your bow vertical or canted? What is your nock height?
Point of impact to the right usually means underspined for a right handed shooter but lets see....try to follow...
Your bow is 58 pounds so 55-60 spine is the "starting point". The old rule of thumb is add one spine group for each inch over 28 so that would put you at 60-65 with a 29 inch arrow. Add another spine group for the heavy head so 65-70. High performance string? add another one (maybe two) so 70-75 or 75-80. High performance bow, add one again (or maybe two since it's a widow
) so that's 75-80 or up to 85-90 depending on if you added one increment or two on the high perf string. Is your draw actually 28 inches or do you pull the head almost to the back of the bow with your 29" arrow? If you are pulling closer to 29 than 28 you might have to go up one more group yet or 90-95. Whew! we're getting up there eh?
So, maybe you are a tad light on spine. I'd try two things. First I'd check the nock hight. Shooting split finger, the bottom of your string nock should most likely be between 1/2" and 3/4" above the shelf. I've personally had problems trying to shoot 3/8" nock hight with broadheads and had them dive into the ground at about 20 yards. Raised the nock and it all went away. Or in a pinch, nock over instead of under just to try it without moving the nock.
Next, if that doesn't help or even if it does help, try cutting a piece of leather like a boot lace and taping it over the side plate directly above the deepest point of the handle and shoot again. If you are overspined, this should compensate by decreasing the amount of center shot and allowing an underspined arrow to fly properly.
If the nock change fixes things you won't have to change your arrows. If building out the side plate does the trick, you need to either shorten your arrows as much as you have room for or go to a lighter head unless you don't mind leaving the strike plate built out. If you are going to leave it built out, get rid of the tape and insert the piece under the existing side plate. If the strike plate makes it even worse, go the other way and remove the added piece and try a 125 grain head.