potting mix for seedlings

Today I sowed seeds of some tropical trees.

Eucalyptus deglupta (rainbow gum)
Ficus Benghalensis SACRED BANYAN TREE
Ficus obliqua (small leaf fig)
Ficus Religiosa BODHI Sacred Fig Tree

Using the paper towel method except I used coffee filters instead of paper towels.

What is a good mix recipe to pot them up in after they sprout.

I personally use standard potting mix, make sure its potting mix and not potting soil. Seedlings usually need a bit more support than regular bonsai soil can provide. IMO