(...)
The problem is, Procession says "You may play an action card from your hand twice. (...)", so if you have an action card in your hand, playing a Procession always involves a choice.
Wow, how didn't I see that... I thought it still had the Throne Room wording for some reason.
Anyway, there's another way to do better.
Toss in Outpost and Prince, with a Princed Throne Room. Only Copper and Curse are depleted, and you have no treasure and no way to get money in your deck(Z does not give you money). No Ruins in play.
I will argue that the second turn Princed Throne Room is a direct result of the Outpost play, since without it, you would not be able to play a second turn, and you have no choice in the matter whether to play the second turn or not. Thus, it is a direct result of your initial play, which played Outpost.
You only have 9 TR's, 9 Heralds, 9 Golems, an Outpost, and 25 Z's for action cards. Also, you have some unimportant amount of non-Action, non-Treasures(like Province, Duchy, Estate, Silk Road, Gardens... you've pretty much won anyway, why else would you be doing this?)
Turn 1:
Start with only Golem and non-Actions in hand
Prince'd TR plays Golem
* plays 2 TR's, with 2 Golems in hand
** plays 2 Z's twice
** plays 2 Z's and 2 TR's, with 2 Golems in hand
*** plays 2 Z's twice
*** plays 2 Z's and 2 TR's, with 2 Golems in hand
**** plays 2 Z's twice
**** plays 2 Z's and 2 TR's, with 2 Golems in hand
***** plays 2 Z's twice
***** plays 2 Z's, then 2 Heralds
****** hits and plays Z
****** hits and plays Herald
******* hits and plays Herald
******** hits and plays Herald
... for the rest of the Heralds
************ hits and plays Outpost
No actions and no Treasure in hand, Copper and Curse bought out, so no choice to buy.
Turn 2: repeat Turn 1 exactly
The total for each turn is 9 Heralds, 9 Throne Rooms, 9 Golems, 25 Z's, and an Outpost, for 53. Multiply by 2, and we get 106 actions played.