The best, though most PIA way, is to fully shape and fit the handle slabs
(and bolsters if any) in a removable way. Some people use bolts or temporary
pins. Others use super glue. Then remove the handle, etch, and attach the
handle permanently.
Top makers tend to intentionally chamfer the tang/handle junction and/or make
the wood be a couple of thousands proud of the junction. This is because wood
will move anyway and an intentional junction looks better than what you'll
wind up with after it moves.