My tell: 40 ex right now.
If you wait for standard most likely 90 ex. Since EX cost the same FG here and there because of how close the league´s end is, just hold it on. This is my personal recommendation, of course you will do whatever the fuck you want.
Reasoning: The cheapest / most potato +2 arrow quiver is 6 ex in Flashback, 25 ex in bestiary and 40 ex in standard. And this is basically just 1 good stat + 1 arrow.
Your quiver is really good: Accuracy, attack speed, crit and life are extremely desired stats, which leave you with 5 out of 6 good stats but medium rolls.
Such an item does not exist in Flashback right now , you have the best quiver in the league. Why do I say 40 ex and not 20 or 200? Because it´s a realistic price it would sell for considering how much currency people are willing to spend on quivers based on my experience with such GG items. For sure it is worth more than 40 but never will anyone buy it in this temp league for that cash.
I have searched the market in standard and 5 good top70% mods is 90 ex and as comparison I have checked it with Onslaught Quill Spike-Point Arrow Quiver and Entropy Brand Penetrating Arrow Quiver which are very similar to the one you have and both sell for 88 and 90 ex respectively.