Don't know if I'm a guru, but I've heard a lot of people reference giving up after you're -400 or worse and there's a lead team with a scholarship offered and very close to full interest. I'm sure it's possible to close that gap with aggressive competitive recruiting, but in most cases, the cost/benefit analysis wouldn't favor it.
It also depends on how late you are in the process. About halfway through the season I cut guys where I'm still trailing by quite a bit, and sort by Top School or Top 3/5. You'll see 3* and 4* guys pretty often where the Top 10 list is pretty uniformly distributed (something like -20, -40, -60, -80, etc.). This tells me that this prospect has not been recruited by anyone yet, so even if I'm in like 4th place, I may move up pretty quickly on that guy's list. Wait until you build it up to 1st and get a slight lead, and THEN offer the scholarship for the chance at the instant commit. If that doesn't work, then start uncovering pitches and schedule a late-season visit.