Which astro should I use until lvl 50, enhanced determination or +PDEF?

[chrisdab]

Hello, These are the current astros I am keeping, which I think will last me to 70+.

At level 48, I cant decide if I should use the enhanced determination or refined fortitude astros.

[miQQQs]

4 slots - patk crit mdef determination(if orange and v 3+), if not - pdef and in 5 slot determi then