Hi @Anni
Please don’t give up on Holman, the instructions in the pattern have helped you to make a very nice trouser pattern.
Personally, I don’t have any of the books you have mentioned. I’ve been learning from the Winifred Aldrich series, although mine are quite old now and she has new ones out. That said, I find that a lot of the finer details are skipped over in these ‘monkey see, monkey do’ types of books where specific instructions are given and must be followed step-by-step. They don’t go into the actual science of why and how. In the Aldrich book, she just says: Draw inside leg seam 24, 29, 28; curve 24–29 inwards 1.25 cm (24-29 being the line that we discussed on yours from the crotch to the knee).
As with the armhole and sleeve cap, You can create blocks to control the length of the handles using the Bezier function that @KeithFromCanada kindly researched out for us in this chat: Creating Smooth Curves: The Kolson Method.
I just didn’t do it because of the time it took. I just wanted you to know how to use the line that you created to get the correct curve inwards in the upper leg.