I am a writer/artist who is interested in knowledge regarding late-medieval/early-renissance style crossbows. I am working on developing a character who is portrayed as an ace-sharpshooter with a custom/self-built crossbow and need advice recommendations on certain points for the characters crossbow design (I plan on drawing it eventually). In the end I'm looking for something that could actually be built and be a logical/functional design and not something that is pure fantasy.
Now I've read a lot on modern crossbows but that doesnt really help in a medieval setting. The most important parts of the design to me (in order of importance)
1) Farthest effective range possible
2) Accuracy at long distances
3) Power/Stopping Power (Penetration of Plate)
4) Maintainable in the field (I've read bad things about early compound bows and servicing)
5) Repeating (I've seen the 'Zhuge' repeaters, but I need a design that would allow for a scope as well. Could the bolts be fed into the bow on the diagonal?')
I've also seen the double (and even triple bowed) arbalests used by the armies of Ghengis Khan in our local museum but have never seen medieval crossbows use this design.
Any help or insight you could give me would be greatly appreciated.