Load *.mid files into a laptop when you do sequencing on a keyboard. Install a version of "Midi JukeBox" which you can find for free.
Step2
Use the mixer window of Midi JukeBox to adjust different levels, add percussion, solo parts, or even mute them.
Step3
Download the files from your laptop into the MIDI module of your keyboard when you do sequencing on a keyboard. This MIDI module can also drive your drum machine.
Step4
Choose to have your instruments be panned from left to right when sequencing a keyboard, or just have it in stereo.
Step5
Add a "click track" on the 16th part of the sequence you create for your keyboard. If you add a sysex message, you can mute the 16th part on your keyboard, but not on your drum machine, which will then be audible on MIDI Out.
Step6
Use a mixer in which to mix the "click track" as well as the other instruments when you sequence a keyboard. This will allow the drummer to hear the sequence in his headphones.
Step7
Make sure you have an intro that's 8 clicks long when you sequence a keyboard. This will allow the drummer to count four beats, and know to count four more beats for the rest of the band.