I've come up with a workaround, looking at HEC22 seems the clogging factor really just affects the effective width. The workaround is contingent upon having accurate parts which have the grate widths that you want, which can be directly mapped into AGN. So I did a dive into partbuilder, created a copy of a structure part, created 2 new parameters (one a list and the other a calculation). One gotcha (had to go back and fix this) is that when you create a new parameter you cannot change the unit again, so since the part is authored in inches, I created a new parameter to be my new effective width and choose inches. I then added the new part family and size to my structure part list having the new 50% clogging factor. Swapped parts in plan view. Opened AGN, clicked "network details" and "map structure parameters", then "mapping configuration", picked the new part family, went to "grate width" and changed source to the new parameter I made and applied to all fields. Then looking in the network details window it updated! Hope this helps any body else. (see pics below)
