I finally broke down and bought a Dental Vibratory table, and WOW, does it make a difference. I have been using a homemade vibratory table for years and have had a constant issue with bubbles. Now with the dental one which has two levels and variable vibration the bubbles are almost completely gone! I do use wet water and it helps but, the variable speed vibration makes a huge difference.
I bought a Model JT-51 5KG Large Square Vibrator on ebay using a 10% off coupon and free shipping to get the price down some.
The top is covered with rubber to make cleanup simple and has a lip to prevent plaster from running over the edge. It is large enough to hold two HA molds at a time.
To use it, just pour the plaster in the molds, dial up the vibration to get the bubbles out, let it shake for 10-20 seconds and then place the molds on a flat surface to set. It is also large enough to hold my largest homemade production molds with room to spare.
If you can afford one it really does make a difference.