For both of us the Middle-Georgia weather is a pain. It changes faster than the weather in England. I'm in Warner Robins.
About three weeks ago, I think I saw the Horse Head. I didn't see it direct but with averted vision and an OIII filter. Or I was seeing thins. I slew 30 minutes south of Alnitak. I can easily see NGC-2023 nebulosity. Tomorrow evening, March 3rd is supposed to be clear. I shall make my assault on the Horse Head and use my Brand New 7mm Type 6 Nagler. Did you hear Bob Barker in there?
It is highly doubtful that you saw it with an OIII filter. The background nebula that the Horsehead is in (IC 434) has almost zero OIII emission (H-alpha and H-Beta only), so a true OIII filter will basically kill the nebula. Try either a good narrow-band nebula filter like the Lumicon UHC or DGM NPB, or an H-Beta filter like the Lumicon H-Beta. That may give you a fighting chance of seeing the Horsehead. Clear skies to you.
One exception is the old Meade "OIII" filter belonging to a friend. On a night that we could detect the Horsehead without a filter through his 20" Starmaster, we were also able to see it using his Meade filter. An H-beta filter provided the best view, of course. I found out later that the Meade filter allowed H-beta transmission, which made it more a narrowband filter than an OIII filter.