there’s a tool that just doubles the pattern. and pattern efx and pattern automation.
that shortcut is within Paketti. it’s called
it works, and it’s pretty nice and i use it consistently. i think i got assistance from @joule to create it originally.
It’s here if you’re curious to try it out;
What I like to do when creating tracks in Renoise is to first get at least >66.6% finished in a resolution (= bpm, patternsize & lpb combo) I’m happy working in. The numbers are familiar, speed of patternlines wizzing by during playback is still manageable making for a better overview. Then bang in the mogue lpb expanding tool for increased resolution, more possible trickery 
. This can be done multiple times, though keep in mind patterns can’t expand beyond 512 lines.