[Pete]

In lieu of the tool, put a small dab of grease on the valve stem groove, put a dab of grease on the tip of a screwdriver, just enough to hold one keeper, then use the screwdriver as an application tool. Put the keeper in, then repeat for the other keeper. Then release the spring.
This keeps the fingers away from pinchy places.

I have even seen people that build super expensive top fuel drag engines use this method.