Jusr ran some tests to see how much stars affect damage, and I thought I'd post them for anyone interested. All attacks were done on the land practice area, and all ranged shots where done at 10m away.
First I used 2 optical blades. One has no stars and one has 1 range and 1.5 melee. Here's what I got. (all attacks I used weren't affected by modifiers)
Weaker: 10 damage with 5 standing cont. shots
20 with backwards dash ch. shot
57 with melee combo
Stronger: 14 damage with 5 standing cont. shots
25 with backwards dash ch. shot
82 with melee combo
I then repeated this with 2 Ore clubs, one with no stars, one with 6 melee
Weaker: 60 damage with dash melee
72 with melee combo
Stronger: 164 with dash melee
145 with melee combo
Did it once more with 2 Reaper Palms, just for good measure. One had 2 ranged and 1 melee, while the other had 4.5 ranged and melee.
Weaker: 9 damage with 1 standing cont. fire shot
49.5 with standing ch. shot.
48 with melee combo.
Stronger: 13.2 with 1 standing cont. fire shot.
73.5 with standing ch. shot
128 with melee combo