For one song I was working on where the math didn’t work in my favor I did it the manual way similar to what you mentioned with additional patterns.
- Figure out which note in the sequence the pattern ends on → say note 8/9
- Scroll up copy a full 9 notes of the sequence but start from the next note (9/9)
- Jump to the next pattern, paste with skip one until it’s full
- Repeat for the next one
It is rather error prone if you’re not paying full attention with the copy pasta 
. I think at the start I just took the first/start pattern and duplicated it and afterwards went back and retouched the tracks which had sequences that didn’t line up to/divide well with the pattern lengths.
Not the most fun solution but I was going for something specific recreating an existing piece (Uncharted Worlds), so it helped that I knew what I wanted to end with and didn’t need to experiment. I think it was only 2-3 out of 6 tracks where I had to fiddle to line things up.
I’ll have to play with @pt3r ‘s suggestion next time I work on something new, with some careful combination of patterns I probably could have made that work as well.