for example, if l want to give a homebrew class the gloomstalker rangers umbral sight :At 3rd level, you gain darkvision out to a range of 60 feet. If you already have darkvision from your race, its range increases by 30 feet.

Modifier: Set Base->Subtype: Darkvision->Fixed Value: 30

Modifier: Sense->Subtype: Darkvision->Fixed Value: 30

Thanks!

Can l do something like this for Saving throw proficiency? For example, the Gloomstalker rangers 7th level ability: You gain proficiency in Wisdom saving throws. If you already have this proficiency, you instead gain proficiency in Intelligence or Charisma saving throws (your choice).

If so, how?

Modifier: Proficiency->Subtype: Choose an Iron Mind saving Throw

I have been unable to replicate on the character sheet the added darkvision range. I currently have:

Modifier:SetBase->Subtype:Darkvision->FixedValue:60

And

Modifier:Sense->Subtype:Darkvision->FixedValue:60

Yet I'm unable to have the character's Darkvision increase to 120. I believe I've followed the correct paths. Could it be something to do with the Shadar Kai (MotM) species?

Edit: Figured it out. Removed the 'Set Base' Modifier and now it properly shows on Character Sheet.