How do I know what size bow string to get

I just got a bear recurve at a yard sale. It is marked amo66 but I'm not sure what size string I need. I've read online both 3" and 4" shorter is correct. I normally get my compound strings from www.60xcustomstrings.com but I have no idea when it comes to traditional bows. Thanks for any help.

Bout 4in shorter should be close if its to long u can twist it to shorten it up. Depending on the length of the bow will fepend on the brace height, i forget how long my quinn(60in i think) is but i shoot it at about 7-1/4 to 7-3/4in brace height and my string is a little over 56in(found ma tape measure:) ). Also i shoot nothin but twisted strings. My cousin builds them and he built mine but i think 3 rivers sales twisted strings and theyre may be some guys from trad talk on here if so they may know of somone who can build u a sting. Ive attempted it but im not very crafty so i just pay my cousin to do it. Uh also, u can shoot an endless loop( aka compound string accept its for a recurve) but all the ones ive shot wer very loud and did not shoot very well. Also when having a string built take into consideration the age of the bow as older bows wont hold up to the snap of these newer string materials and the amount of strands the string is made out of i have a 16 strand dynaflight and an 8 strand dynaflight the difference in the sound of the two is daylight and dark. The 8 strand is much quieter than the 16

vortex is right 4" shorter should be close. What matters is your brace height. Twist your string till it shoots the best.