Whoa, quite a question. Too many variables here for me. If the client didn't tell you what they want I think it's up to you. But I have one more variable to throw in the pot. I did 32 for my nieces wedding.
She picked the font and placement. The ladies were done with the point of the hankie at the bottom of the initial. Mens were the other way so they would be right side up if folded and used in a suit jacket pocket. One more thing to think about. Good luck.

1. An answer is near the bottom of the first site.
2. Another answer site.
3. Another answer site.
I think you should use them as guidelines but also use your own opinion depending on the use intended for the hankie.

The only thing I can add is the outer edges of a folded napkin should face the plate on the left side , next to the plate Many people put the edges to the outside in a place setting which is incorrect. your fingers are to pick up the napkin edges next to plate not folded away from the plate. I guess this applies to hankies also.

At Embroidery Library under placements and guides there is a cool chart that tells the proper placement for lots of monograming and designs. Might help.