And the "filled" grain will remain that way until the uncured oil down in the wood cures... oils shrink as they cure and those pores will telegraph very soon.
There is nothing tung oil does any better than linseed oil. "Boiled linseed oil" is simply low grade oil sold in hardware stores with lots of garbage added. Tung oil tends to be higher grade oil when purchased because none of it goes to "food grade," because many people are allergic to tung.
The finishing industry substitutes each for the other and many tung oil finishes have absolutely no tung oil in them.
There are many different ways to fill wood pores but none are as bad as sanding slurry left in them. Please make a sample board sometime with several different finishes, including wet-sanded slurry. If you do not see the loss in depth and luster you need to get your script changed. Shellac makes a great sealer for woods that will not be used in bad weather. It sticks to everything and about everything sticks to shellac.
Because oils used to be very expensive and often very old, hand-rubbing was a reasonable application method. Today, it is far easier to apply oil rather heavily and quickly. Then let cure for 10-15 minutes before wiping completely dry. Lots of coats can be applied quickly and will build to a beautiful luster.
