Okay first off thanks for such a helpful response i've absorbed some good info here.

To answer the question at the bottom of the post i think it's because;

7.43/(7.43+2.70) = 0.73 so if i fold more than 73% of the time villain can 5 bet any two cards profitably.

But with his 3 bet sizing i have to fold more than 60% for him to be able to 3bet any two cards profitably against me.

So to avoid being exploited by folding to much to 5bets i will have to fold 73% which means i'm calling 27%.

Also to avoid being exploited by 3bets i will fold 60% which means i'm calling or 4betting the remaining 40% of the time.

I thought that would be the answer but i'm obviously wrong.

I'm going to bed it's pretty late i'll try and figure this out tomorrow with a fresh head. Also i'll see how my second range plays out using what i've learned here.