If your front blinkers only have two wires, then forget about the running lights and only use the signal and ground wires.
Since they're LED (a glorified diode), you could use a meter with diode tester or continuity setting to check which wire is ground. The LED will either be forward or reversed biased.
Or, you could use your battery instead of the meter.
BTW I can relate to the wiring issues. The previous owner of my bikes utterly butchered the wiring harnesses installing cheap-ass front flush mounts and a hotbodies undertail.
I had to replace all wiring harnesses, undertail, rear fender, front & rear blinkers, etc., to do the job right.