The "Constant" measurements for using the MB-102 as a FVB...

[cbwx34]

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the impression that this system is only useful on straight blades without curvature otherwise the angle changes by raising the knife to follow the curve..
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In addition to what Rick said... angle change in the belly to tip area is controlled by how you clamp the knife in relation to the curve, clamping it so it maintains the same angle as you lift/rotate it, etc.

Check out the Advanced Knife Sharpening video for this and other tips.

[tgbto]

I think in this case your best help is the sharpie: mark the whole edge along the entire length of the blade. Take a stroke, look (use a magnifier if necessary) at where your sharpie is removed.

If only the shoulder of the edge is honed at some point, you might want to start lifting up the handle a bit earlier as it increases the sharpening angle. If it feels akward, you can rotate so the edge is closer to the USB. Conversely, if only the part close to the apex is ground, you can rotate so the edge gets further from the USB.

The MB-102 does not change anything compared to the VUSB, so if you use the same angles and lift/rotate consistently between the grinding and honing phase you should be OK.

There are countless posts on lifting and pivoting, you might want to read some. AFAIC, I lift so it "feels right" (judging by sound/water flow/black gunk flying off/tactile feedback/whatever you're attuned to), and then rotate as necessary to get the edge I want. Sometimes in one direction and then the other, depending on the geometry of the blade. That's the part of the sharpening experience that is hard to capture through jigs settings and calculators... But it's a fundamental one on complex geometries.