Straight Arm Freestyle

Hi Everyone :) Here's a little bit about myself. I live in Pakistan, Islamabad. I'm eighteen years old and am a member of the Islamabad team. I've been swimming seriously for about year now, though I have been in and out of the pool from a young age. I am aiming to make the national team. So recently I've been experimenting with my freestyle. I have started using a straight arm recovery in short distance events and at the end of a long race. People in Pakistan aren't familiar with this style so I am a little bit in the dark as to what type of catch to use. Should I just drive my hand straight down and back or should I use a deep or a short catch? Any information about the straight arm freestyle would be very appreciated :)