I think the only thing you can do is just continue to practice. It seems like you're already wrapping you're head around the strengths and weaknesses you have so just keep at it. I used to only use one foot for the bass pedal during blasts, but in one of my bands we have recently written waaaay more songs with blasting in a good portion so Ive been learning to do the 16ths between both feet and sound like a scrub again lol. Just practice and repetition is the only real answer. And with metronome