Lately I'm praciting on Bullet For My Valentine's Scream Aim Fire and As I lay Dying's The Darkest Nights.

I noticed, in both songs, between picks the lead guitarist is doing one or few palm mute open picks on the 6th frets.

Tabs example:

I'm trying to do it and I find it extremely hard to hit the palm mute part between picks.

Any tips or things I should know that might make it easier for me?
Personally, I'd just keep the low E string palm muted at all times since it looks like the only palm muted notes are on that string.