Why are the numbers inside the tag needed? As far as I can tell, changing them doesn't actually do anything, except that if they aren't there the tag doesn't work.
[glow=red,2,300]
[glow=red,2,900]
[glow=red,9,300]
[glow=red,9,900]
[glow=red,1,300]
[glow=red,1,100]
[glow=red,300][glow=red,300][/glow]
[glow=red,1]
[glow=red][glow=red][/glow]
PSEUDO-EDIT: Well, it looks like only the first number is needed, but it still doesn't actually change anything about the appearance...
[glow=red,0]
[glow=red,2]
[glow=red,9]
[glow=red,10]
[glow=red,99]
[glow=red,100]
[glow=red,199]
[glow=red,200]
[glow=red,299]
[glow=red,300][glow=red,300][/glow]