I think Old Glory would be massively over scale - there is a british manufacturer 'Tumbling Dice' who do a range of actual 1/72 metal figures which are absolutely compatible with plastics and this includes crossbowmen - there is one in their Norman/Breton range which I expect would be most appropriate for the Crusades and a couple in their War of the Roses range which might not match so well. Here is their website
Check out Thunderbolt Mountain's 25 mm Arthurian range. Though somewhat taller than most 1/72 plastic sets, they are much truer to human proportions than most metal sculpts. Unfortunately the crossbowman they offer is probably over-armored (chainmail, helm and quilted gambeson) for the Crusades.