The receivables account is set on the customer, and the Variant Rules matrix can choose a component variant per size.
Trade Receivables Account on Customer Master
The Customer Master dialog now has a picker for the customer's Trade Receivables GL account, which invoice posting needs.
Component Variant per Parent Variant
The BOM Variant Rules matrix can now pick which variant of a component each finished-good variant consumes (for example a 6 mm or 8 mm bow per size), with "Set all" per row and column. Rules the matrix does not own are shown locked rather than overwritten.