your percentage will be based on several factors such as C&P exam, treatment history, your docs NARSUM and your commands NMA along with any statements you submitted.
As for PDRL vs TDRL that's easier to narrow down. The DOD looks at only the unfitting condition. If your only unfitting condition is PTSD then you will most likely get TDRL, as with most mental health conditions, so that they can see how the condition changes once you are out. They want to make sure your stable before assigning a final rating incase you get worse or better. Good news is if they put you on TDRL, you will be eligible to collect on a rate of 50% until you are re-evaluated at which time you will be assigned a rating and/or continue on TDRL or be placed on PDRL. these re-evaluations will continue at a minimum of 1 every 18 months for up to 5 years.