IMO 95% of your finished product is learning your cooker,and how to COOK the meat.
The wood,sauce,rub,special tricks are the other 5%.
There are great products out there ,that great cooks have developed.
Experienced cooks will say-buy them and tweek to your special needs and get on with COOKING.
Now if you are a huge volume user,you might pay a chemist to design and make by the ton.
Just my $0.02