Panama National with Ajman Visa. Please advise processing days for L and M type and requirements?

Do you want to visit HK and mainland together? If so, you should apply for two. One is for mainland China and the other is for HK.

L or M type for mainland:
Basic requirements are the same, passport, application form and recent six months passport photo. For L type, you need to provide an invitation letter. If you can't, then round-trip air tickets and hotel booking are required. For M type, invitation letter from your business partner in China and the one from the duly authorized unit are required.

Since you just transit in HK for a day, I think a transit type is ok. Your passport, finished ID1003A form, a recent passport photo and your flight itnerary are required.