I checked up on this topic and was happy to see some replies. I've used the pressure feature to try to emulate the control that the line width tool gives but am not satisfied. I think the main issue is that it is essentially creating another set of arbitrary nodes that are distributed along the line, but that cannot be seen directly or manipulated exactly where you want them. I think a graph is a clunky way to implement the feature of thickening a line. In Affinity it seems that if you want a part of a stroke thickened you need to estimate what precent along the stroke the area is, then go to the pressure graph and try raise a point at an equivalent precent distance along that graph. Why make it so hard? Sometimes I have a corner node I want thickened, not just before the node, or an estimate of almost the node. Problem compounds when paths have many nodes