I actually like the idea of gluing on additional weight onto balance wheel. Simpler easier, also since a clock no worries about positional error. Errors watches undergo in relation to gravity. Ex. horizontal balance is unaffected by gravity. Vertical is.
Poising a balance wheel in the watch world, is accomplishing even distributed weight on the balance wheel by adding or removing weight.
The balance wheels in this case often have screws in the rim so that not only can weights be added or subtracted, the screws themselves can be screwed in or out to adjust time keeping, effecting the centrifugal motion. In = faster, out = slower.
The watch balance being more critical due to varying relationship with different angles to gravity has these screw system as more precise means of control. Rims of watch balances are also split, the ends are designed to spread out or curl in depending on weather conditions. The rims are bi-metalic strips, differing metal has different cold/heat reaction. Joining the two causes a curl when temperatures change. The reason was because temperature changes effect the hairspring as well.
An amazing race to perfection, stuck in the physical world.
The poising tool is like a tiny bench vice with two thin jeweled edges. Most have a float bubble and legs that adjust so that the two jewel edges are adjusted perfectly horizontal.
The poising tool jewel blades are then adjusted to the correct width so that both balance wheel pivot ride one on each jewel edge. The edges about inch long. Perfectly parallel to each other.
So, now the trick is to slightly touch the balance wheel so it begins to roll on those jeweled edges If there is a heavy side on the balance it is noted and adjustment is made by either adding weight or subtracting. The balance rim itself can be drilled to remove weight if desired. A special tool takes weight out of screws by drilling center of screws. However more difficult to use.
So the balance, out of movement, hairspring removed, rolls on these two jewelled edges. If it slowly rolls to a stop then the wheel is correct, no heavy spot detected. However, a heavy spot will rock back and forth, heavy side down.
The fine jewelled edges are required because they provide the least resistance. The weight differences are very small.
As time progressed the hairspring issues where more thoroughly addressed. The advance of the overcoil and later more temperature resistant alloys where steps that got rid of the split rim with balance weights and screws.
Amazing how much simpler things become when the correct issues are addressed.