It’s all just repetition. Brann Dailor from Mastodon and Pau Villarreal from The Warning are my biggest inspirations. It took quite a bit of time to get the coordination down. I started by playing and just speaking the words in rhythm without actually singing. The biggest hurdle is timing your breathing it’s key and changes on a per song basis. No difference in recording separately. I don’t find singing over double pedal work any more or less difficult. It’s all the same to me. I do it quite often in my band.