Spanky,
BC foreend is maybe 3" longer than the schnabel foreend on the gun Gendoc posted. There is a recent post in this forum of a BC foreend on a 22" 45/70 that might help you visualize. ALso, I think the BC foreend length is in the FAQs, but not sure on that one. IMO the Mannlicher would really good on an 18" barrel, plus GSI gives you a lot more material/finish options. ALso, GSI makes Schnable foreends for the Handi so you could go walnut, maple, laminate etc. if you want.
Sounds like you are building a very nice 44, good luck with your project.
BB