Position of a pattern-matched part of an expression

What you have

A pattern, with certain part of it labeled

As an example — Label: wally
```
pattern = h : HoldPattern@f[x, __, 3[5], wally_, y]
```

An expression that matches a pattern such as:
```
expr = f[x, 9, v, h[v], 3[5], v, y]
```

What I want

The position of the part of the expression expr that matched the label wally.

In the above example, that would be

gimmeWhattaWanna[expr, pattern, wally]
(* {{6}} *)

Note

If the labeled pattern is a sequence such as wally__, either finding the position of the first, or the first and last, are acceptable. If the labeled pattern is repeated such as in f[wally_, 2, wally_], then a list of the positions seems the most natural solution. However, a solution that limits itself to non-repeated labels, or even non-sequence ones is useful.

Comments

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I have several sigmoidal fits to 3 different datasets, with mean fit predictions plus the 95% confidence limits (not symmetrical around the mean) and the actual data. I would now like to show these different 2D plots projected in 3D as in but then using proper perspective. In the link here they give some solutions to combine the plots using isometric perspective, but I would like to use proper 3 point perspective. Any thoughts? Also any way to show the mean points per time point for each series plus or minus the standard error on the mean would be cool too, either using points+vertical bars, or using spheres plus tubes. Below are some test data and the fit function I am using. Note that I am working on a logit(proportion) scale and that the final vertical scale is Log10(percentage). (* some test data *) data = Table[Null, {i, 4}]; data[[1]] = {{1, -5.8}, {2, -5.4}, {3, -0.8}, {4, -0.2}, {5, 4.6}, {1, -6.4}, {2, -5.6}, {3, -0.7}, {4, 0.04}, {5, 1.0}, {1, -6.8}, {2, -4.7}, {3, -1.

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