...You cant calculate slipfactor from DPS and armlength...
Not for a single stroke but as estimated average:
SF = [SPL x (SW-Sh)-(PL-PO)]/(PL-PO)
SPL: Strokes Per Length
OK, uncertain is the amount of shoulder-shrugg (influences as Sh as from 0 [from left/right collarbone in swim direction] to 1*Sh [collarbone always rectangular to swim direction], think half Shoulderwidth is an acceptable approximation), and you have to include the length for catch-setting from front to full traction (in your example it is)... but even an "overgliding" is considered, because you have to pay it with acceleration and there the slip is included again...