I understand the concern and well I guess its too much of a risk with the brilliantly running motor that I have right now. I might give it a pass at the moment.
However, just curious - isn't this the same thing which happen when we use the Cast iron engine cams in the AVL with the small base circle and which results in a higher lift on the same.
The Iron Barrel cams are smaller base circle, yes.
However, they are ground with all the necessary attributes to work as a proper cam in a valve train.
A cam is not just a bump on a wheel. There is the base circle, lash ramps, flanks, nose, included on the cam shape which have functions defined by multiple polynomial curves. These curves translate the progressively different lift rates at various portions of the lift cycle which can be controlled by the valve springs. The lash ramps have a certain length and lift acceleration, so that the lash is taken up gently, and doesn't hammer the valve train. The lift cycle is then begun at a slow acceleration, gradually increasing with different mathematical curves blended together to a smooth acceleration curve, and then after reaching the maximum lift rate part-way along the flank, it gradually begins to reduce the lift rate so that it can get over the nose without flinging the valve out of contact. Additionally, flat tappet cams have a slight taper on the lobe and they are not "flat". This taper causes the tappet to spin during operation, so that it has a better wear life. And the surface is hardened to a high hardness for wear resistance under heavy loading, and after any re-shaping might be done by a professional grinder, the surface is re-hardened to restore the wear resistance of the metal surface.
The reason that they use a cam grinder to do this grinding is because these contours must perfectly follow the mathematical curves programmed into it, and also grind a perfectly smooth contoured surface. This surface which is required cannot be met with normal machine cutting tools, much less a hand file. It needs a precision grinding machine. A cam in an engine is a very complicated piece of engineering that requires specialty knowledge to design, and special tooling to make
None of these geometrical attributes are met by "hand filing" the cam down, and if your diagram was any indication, the plan was to file down practically everything but the nose.
So no, it is not at all the same as using the Iron Barrel cams. The Iron Barrel cams may be somewhat crude, but at least they have the necessary design attributes.
The bottom line is that you can't just go filing these things down in your workshop and expect decent results. It might "work" in terms that the engine will go around and still run, but there will be problems associated with it which may not be initially apparent.
On top of that, the springs may not be(probably are not) able to handle the more rapid accelerations of a faster lift cam, and also might not have enough room between the coils to take that added lift without hitting coil bind. If you have not measured this, then you don't know. And we already know that the AVL has horrible valve springs that can't even control the valve properly in a normal application with normal cams. Then, we would have to see if there is enough room to lift the valve that much without hitting the valve guide. We have to measure that. Then we have to measure if the valve is going to hit the piston as it goes over TDC.
There's just a lot more to this than you might think.
I can spec-out a cam with all the necessary parameters, but I go to a cam grinder to get it made. I wouldn't try to re-profile a cam, and I have a full CNC machine shop at my disposal.