Welcome and thanks for the bug report.
First problem is that you have found a bug
Right now there are 2 ways around it. First off, you could put the line:
Plectrum Tuning g- d a d+
Before the define.
Or, forget about the define and just use the pattern right in the main section:
Sequence {1.0 +3 120 120 120 100;
2.5 -1 - - 80 80;
3.0 +4 120 120 120 100;
4.0 +2 90 80 80 80; }
Now, to some of the questions:
Do I need a groove? Nope. But it will make what you do today much more usable tomorrow. AND, even if you don't want to stick the thing in a library file, you'll be amazed when you create 2 to 3 similar grooves (add strings, drums, etc) and call them up in the song.
As to the "sometimes we use define, sometimes we don't" ... well, I think if I were doing it all again I might not bother with define. When I started out, I thought I needed it for speed. I was wrong.
On the other hand, I use it all the time from the INCLUDEs.
If you are using the same pattern over and over again it gets tedious retyping it all over. And, defines are complied so it sound be faster.
Also, depends on the sequence size. If you have 1 bar seqs it probably doesn't matter that much ... if you have 4 bar patterns (highly recommended) then you'll find define very handy.
Hope all this helps.
I now need to study the code and see what needs to be done to fix the tuning/define problem.
Let us know if this helps, etc.
Best,