Hi,
i understand that the push type will be stronger but for a jump i will need abrupt release of energy that i think i will get from a pull type.what do you think?
I think you shouldn't waste peoples time asking questions if you already made up your mind!
It's simple math. The more power the better (up to a limit of course).
The spring return is much weaker, as the solenoid need the power to do its work AND the power to overcome the spring return at the same time.
That's how it is, but do whatever you feel like.