TRANSITIONING FROM 3/8 WOOD TO TILE(APPROX. 5/8) OVER A WOOD SUBFLOOR. HOW DO GET THE PROPER TRANSITION TO SIT RIGHT?WHICH TRANSITION IS BEST ?

You could retrofit a baby threshold by cutting the bottom part off. Or glue a 1/8" piece of wood under one side of a tmolding.

You can use a "T" molding.

The key with different heights and a "T" molding, is the higher flooring must be cut perfectly straight. The "T" molding barely sits over the higher flooring, so there is not a big gap under it, from sitting at that slight angle.