Thanks for the reply, Steve M.

Here's my scenario for this week:

-I'm in Shekou and have a noon flight to PEK on Wednesday out of HKIA
-Taxes already paid
-I can use the ferry for Y260 or a mini-van for Y150
-I'm fine with the ferry, but have never done so previously
*can you explain where the tax refund happens?
*is a 10a ferry okay for a noon flight?
-I will surely need to "enter" China upon arrival in Beijing, but where would I exit in this scenario?