Look — I'm not gonna say it's wrong, but putting the Big Muff after the Tube Screamer in that chain might be a bit counterproductive. You're definitely losing some clarity there, with the Muff's heaviness clouding the TS9's smooth overdrive. I’d suggest trying the Big Muff first for that thick fuzz and then hitting it with the TS9 to boost it, which could give you a more pronounced lead tone. Just a thought!