Non-Casters and summoning spell runes

Which is pretty nonspecific to what can be done and what can’t. I would assume pretty much all divine spells (and sarishan) can be gotten in runes, considering that priests of all types are common in the first city. I would assume most arcane casters might be more cagey about offering their services. But those are only assumptions, and different people assume radically different things. Should there be a ruling about runes? Is it pretty much true that we can get any non-spell rune that we might want?

To follow up on this request for clarifications, I know that Treasures for the Ages says (pg 4) that all the optional rules for runes in green are in effect in the campaign, I assume this means runes scale by tier? The pdf version I purchased doesn’t have color.

Legends of Arcanis Campaign & Optional Rules

All optional rules in green are standard for the Legends of Arcanis Campaign. For more information
on the campaign and its library of free adventures see http://www.LegendsofArcanis.com

I suspect the book was written in color but the final was rendered bw for cost.