I had a cheap one, can't remember the name, worked fine. Plus or minus a fps ow two. got another cheap one [but not cheapest] coming early next week. I think these economy models will work fine for comaprison purposes. I'm gonna see where the bear boogered the buckwheat on this string thing!! Smoke: I can get one of my L II's up to 474 gr by adding weight to 431. If ya wanna know what they are coming out of your Phoenix at. Or, I'll send it on to ya to check your stuff out in a week or so. Gee, V-zone or chrony???? That's a tough one!! lol. Get the Zone, I'll borry ya the chrony!!! Dan