I am not sure if you are asking a question or if this a statement?

I think it helps if the heights are reasonably alike, but of course, the widths will vary - such as A and I or I and w.

it is not necessary, but looks better if they are of same height. no matter what, the letters will always very some in the width.

Often, larger-sized embroidery fonts (3 inches or 76 mm and larger) are used as single designs. Therefore, they need not be the exact height. If using multiple alphabets of different heights, try centering them vertically so there will be a small difference between the top and bottom of each letter rather than a larger difference at the top or bottom. I hope this is clear to you.

Are you getting the answers that you want. I suggest that you ask your question in your language and there will be others here who will understand

I believe that it is. For example I just did 5 stockings for a customer with the names on them. It would not look uniform if the letters were of different height. IF you have a font set that the letters aren't uniform, you would only use it when doing a single application.

I've found that some of my fonts are not all the same height. So if I'm using just captial letters, they are not even sizes both vertical and/or horizontal.. Same for lower case letters. It would be nice if they were digitized so that all letters were the same height and width, but somsetimes you just have to deal with it if they are not.

I think when we put letters together to create names or words, that if the style of the font letters are the same, and the size of the letters are also similar, then you can often combine letters from different sets easily. The closer the letters are to each other on our stitched projects, then the closer the similarly needs to be in order for them to look like all the letters are from the same set of designs. For instance many of us have collected many of the freebies from font sets and may be missing a letter or two and if we are not able to afford the missing letters, or just wanting to use what we already have, then we often may have a letter from another set that will go with the other letters we are using perfectly fine; especially once we stitch them all in the same color and have added the little extras that are often found in the sets, thus even with a letter added you likely could never tell the letter had not been part of the original set. I also agree that not all letters of a similar style would go well together as each font creator has digitized the designs uniquely to their own style using different textures, stitch lengths and direction of stitching but I find it part of the fun to see how I can mix various designs together to create projects using the designs I have already acquired. Happy stitching as we all are now entering this holiday season.