Well, you’re going to get a lot of varying opinions. Personally–I try to never use align to baseline grid. I work in book publishing, and align to baseline is a pain in the butt.
For your spacing, be warned that I worked in points and picas.
The general rule of thumb is 20 percent. That is, your leading is 20% of your type size. For example, if your type is 10 point, your leading would be 12 point. This is not written in stone. You can have a head that is 11 point with 12 lead, or even 9 point type with 12 leading. The 20% is just a starting point.
For spacing above and below heads, you want to keep it even. If your head is 11 point with 12 point type and you want a line space above it, you would put 12 points (or 1 pica) in the space above. But suppose you wanted a bit of space below the head. Then you could make it 9 points above, 3 points below (which equals 12). Or if you wanted more space above the head and below, you could have 18 points (1p6) above and 6 points below. Remember the 12 thing as that’s your leading. And in the latter instance, the space above/below equaled 24 points, which is based on 12s. The main thing is you want your style sheets to be on even lines.
And you want to set up your baseline grid in your preferences for the leading of your job. And set where the first line begins so that it aligns with your first text line. Once you set that up, there is no need for lock to baseline grid.
If things aren’t set up for even lines and your grid not set correctly, align to baseline grid will do wacky stuff.
If you do use align to baseline grid, never use it on subheads or text following subheads.
.
