We've used both methods on our 2001 Adventurer with the 19.5" wheels. Both seemed to work well. The only cautions if us use Equal or some other similar brand are to have new valve stems with about a 2" straight length installed and use vakves that have filters.
The first time we used Equal on the front tires we had problems with material getting in the valve every time we checked tire pressure. Even though we had the valves with the filters installed the stems were curved enough in the filter area that the filters couldn't seal against the side of the stems. We had to change out the stems for ones with a longer straight area so the filters would seal on all sides.