Optimas doent need to be vented as they have a gel interior as opposed to the lead acid type that need vented. Optimas were designed for trunk mounted applications years ago, mainly that of drage racers who need a better weight distibution.
An Optima does not have to vent due to the gel interior. It can be mounted in any position also.
You're close...... Optima batteries DO HAVE BATTERY ACID in them just like
any other battery does, ITS NOT GEL ! It is called AGM (Absorbed Glass Mat)
The acid is absorbed into a glass mat, hence no spill or gases.