joachim, those are good ideas, questions, and considerations, but let me tell you the real secret. Marc is simply a MASTER at tiller. And that's the truth. Like Kurt Russell in "Big Trouble let in Little China" Marc can "see things no one else can see, do things no one else can do".
This bow is high draw weight, fairly narrow (though it retains it's width out the limb, as you said) and only 62" long or so, so tip weight is less of a problem IN THIS PARTICULAR BOW. But, did you notice how Marc made TWO almost identical bows, aside from a few lbs draw weight from two different woods? LIKE IT WAS NOTHING!? To me, that's almost the same as magic. Their strung and unstrung profiles are literally so close that you could superimpose them and the only difference would be any knots or bumps. The knowledge of where to be d, and how much, and the different width and thickness needs for each wood, and the subtle understanding of how to make one part bend JUST slightly more or less, and the eye that takes on the tiller tree...... that's simply high skill.
Now, I have successfully made well over a hundred bows at this point, and started many, many more that I pushed and learned on until they broke, but if I started out with two good clean staves to make two almost identical bows, I almost couldn't do it. The draw weights, or the amount of that tiny tip reflex he gives each one, or something would be different.
It sounds like I'm just brown - nosing Marc, but all I am really saying is that DESIGN and TILLER still rule. Nothing will co.pensate. And, I'm STILL training my eye, after almost 18 years of this.