Markings are based on skin color. If you're avoiding letting the sky sap change skin color allow it to do "pale green". You can always change your skin color later.
I think Sylvanol only has blue markings, although I might be wrong. It's been a long time since I wrote it. Use Pickmentation, as Zevos said.
I keep getting the glowing violet ones, but I want the green ones, and I'm getting really tired of reloading...
Sylvanol:
Au Myrtille -
- No "Vanae Markings" status effect
Au Ronce -
- 1/4 chance to:
- Gain "Vanae Markings" status effect
- Change skin accent color to luminous blue, luminous green, luminous pink, luminous silver, or glowing gold
- No "Vanae Markings" status effect
That's what the wiki says and from numerous uses I'd say it's pretty accurate Couch seeing as you wrote the item
- 1/4 chance to:
- Gain "Vanae Markings" status effect
- Change skin accent color to glittering black, glowing red, glowing violet, or luminous silver
You can use Pickmentation to recolor your markings.