I have the violette Alma MM and I also have Speedies so I can empathize with how you are conflicted with getting your vernis Alma MM or to add more Speedy bags to your collection. From what I experienced, I found that it was best to "answer" the biggest voice in your head first. lol Which bag is screaming at you the loudest? Which sets your heart afire and will give you that ultimate handbag high?
Getting three Speedies sounds wonderful (who wouldn't want more?), but since you have the money now to purchase the Alma and if this is the bag that is calling out your name the loudest, then by all means, you would feel better getting the Alma first.
The other Speedies are easier to save for since they don't cost as much.
Good luck with your decision!