Yes, the hose ends are specific to the type of hose you use. Also, there are different hose end manufacturers. I really don't like Earl's but Summit and Aeroquip are really nice. the Earl's ones are basically single use, especially the ones for rubber hose. The rubber gets jammed in them and they are impossible to clean and use again.
I did use The teflon lined stuff for my locker lines. I want to say i used -3.
If I were you i'd make the leader hose out of the teflon lined stuff and use -6 like you are planning. you could probably get away with using the braided rubber hose but the cost difference won't be that much and the teflon stuff will never give you any trouble. It's ridiculous the heat and pressure they are rated for.