I'll have to disagree with you here, Minn...but I think it's only a matter of how people think, really.

You're absolutely right...there's no reason you can't simply be "in the range", and then fly, adjust, fly, etc until it's where you want it. To be sure, where the CG "should" be is very much a subjective thing.

However, for several reasons, I still prefer having and recommending the Vanessa:

1) Some of us are weirdos We prefer to make known changes to the CG, and then "measure" results, rather than "hunt around" for a CG we like. It's really six of one and half a dozen of the other, admittedly...I just happen to think in terms of "Eh...I think the CG needs to come back 1/2" " as opposed to "I think i need another ounce in the tail".

2) While I agree with you that "close enough" usually is, if we combine 'close enough" with "not quite in line" or whatever...we can get pretty far out of whack. For beginners especially, but really all of us, it's pretty easy to miss by a significant margin when balancing some of the 'tougher" planes. A big bipe, or a long nose moment that makes it tough to get fingers under the wings, or trouble telling when the plane's level as the OP noted...any of these things can have you miss by enough to make the first few flights "adventurous". The Vanessa takes that out of the equation, and gives us some real precision.

3) Probably the biggest thing I see (and it's often argued with) is the ability to "experiment" with the Vanessa. Take a new scratch build for example...we need to move the CG quite a bit forward, maybe. Can't just "go fly and then adjust". And putting "some weight" here or there, and then back on the balancer, then 'some more weight" or "move that weight", and then back up, etc etc...real PITA there. The Vanessa let's me examine ALL the possible ways to achieve that change of CG, without ever coming out of the harness. Just drop a single ounce at a known distance from the Cg, quick twist of the dowel to re-level the plane, and it's nothing but math from there on out. Or, if you don't want to do math, you can add/remove/move weight all day long, and never pull the airplane out of the harness.

One last little tidbit too...especially appropriate in the beginner forum, imo.

I've found with students...and heck, even my own kids...that NOTHING teaches airplane balancing better than this thing. It's a WONDERFUL tool for understanding that WxA=M, and how that relationship impacts the airplane...they can SEE the airplane, quite literally IN THE AIR, and even press/lift on one end or the other to see how changes in CG effect the sensitivity of tail surfaces, pitch and yaw, etc.

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Like I say...I agree with you for the most part...CG really is something VERY subjective (Within, of course, the limits of the aircraft), and there's no need for perfection. If the Vanessa were a few hundred bucks, I'd absolutely agree that it shouldn't be used.

But with it being cheap (< $20 in material), easy to assemble and use, versatile as heck, AND a pretty darn fine educational tool, I can't help but recommend it for anyone in the hobby.