... it seems like it was more difficult to find last time I bought some.

On finished wood, I didn't seem to have that much of an issue, I cleaned the wood with acetone or mineral spirits first, used a Scotch pad to lightly scuff, vacuumed that off and second wipe down with spirits, may have even used a tack cloth, then I applied the Watco w/a foam brush, fairly light, let it soak in, went over it a 2nd and 3rd time while still wet, then before it tacked off, gently wiped with clean soft cotton cloth.

Cheers, John