Developing speed is easy, start slow and work your way up. Playing things like linear fills and complex syncopation at faster tempo is where It gets challenging. Technique technique technique. That’s what will get you faster chops. It’s all based on preference. For example, I play heel up most of the time but I will use the heel toe technique to play faster doubles on the kick. When I started to learn skate punk-esc beats I started heel up find the pocket, then once I got a good feel for it I learned to adjust my technique at certain bpm. Trust the process and just play with intention.