Yeah, I for some reason wrote two when I meant three above. I can't even blame mistyping there.
Since I made a mistake, I'm going to better explain my rationale. It's a matter of diminishing returns, 50 CrCo lab total is pretty easy to get to. Above and beyond that it gets significantly more difficult (and expensive) to increase the lab total. Finding a 70 isn't difficult, but it is expensive. I've been toying with turning Ra'am from Phoenix into a longevity specialist. In about 11 years (to him that would be 1224), which includes some time for adventure, finding a familiar, binding it, and getting an apprentice, with the resources available to him at Phoenix, and after refining his lab fully (+7) and installing things that specialize longevity rituals and/or creo he can get to a LT of 60 for Longevity Rituals. If the recipient is at 35 years of age, the ritual requires 7 pawns and he can add up to 13 more pawns (10x2), which gets him to a 99 and takes advantage of the familiar and two assistants who add another +20 (might be a bit high, but not unreasonable)!
Holy crap, that's better than I thought it could be.