See Designing With Vilcraft by James Fisher. Not directly applicable, but there is some information in the publication on estimating chord widths for joist girders that may be able to be applied to the LH series joists you mentioned to get a ballpark width. There may be some similar methods to directly estimate chord widths for joists, but I would have to do a bit more digging to come up with a reference.
Otherwise, you might try reaching out to a joist supplier. I have a good relationship with engineers at a local joist manufacturer that I can run a question or 2 by every once in a while.