Hand filing is slower but more precise and forgiving.
From what I understand, there's really only 2 oils for wood finishes, linseed and tung.
Teak and danish oils don't really exsist, except as marketing terms. Finishes labeled as "tung oil finish" and "tung oil varnish" are also in this category.
These type finishes can have tung or linseed oils, or something else. They will also usually contain varnish and thinner. Some might include wax.
There's just really no way of knowing what you have unless you get 100% tung or linseed oil.
I've used some of the blended stuff, and it works ok, but like 100% tung oil.
Whatever you use, don't apply too thick of coats without removing the excess within an hour or so.
I soak in alcohol to remove a thin layer of the wood's natural oil, so it will absorb the tung oil better and provide what I feel is a better bond, and more durable seal. A side benefit to the alcohol soak is removing the natural oil lightens the color, slightly offsetting the darkening effect of tung oil. This results in the wood coming out closer to its natural color.
There are some woods that are naturally very oily. and unless you need a harder more durable coat, they are just fine in the raw, it just depends on what they're exsposed to.