it depends on the hardware store rod . Some now days are actually using Ramin , those are good rods if you pick and chose one with good grain .
But again you have to take the time to see what it is they are selling you . If you don’t , you just may find on through your hand. Been there and have the scar to prove it .
As to curly maple . I don’t recommend it . While it would be a very nice , showy rod . It would be weak and great care would have to be taken with it . As was said by another poster . You want a rod , free of knotts or grain run out . IE you want the grain to run full leaght if possible
Now if your speaking of barber pole type rods . Simply use masking tape and wrap the rod , leaving a space between the tape as you twist up the rod . Then come back and stain .
On the subject of Coal oil . Keep in mind that Kerosene is not coal oil .
Basically what soaking does is two things
1) the oil softens the fibers , making the rod alittle more resistant to breakage during deflection
2) it keeps moisture out very well . If you have ever had a wood RR swell in wet weather , you know that its near if not impossible to remove . The coal oil prevents that swelling from happening
Lastly if you use a wood RR , do not neglect it . It needs to be cleaned and greased . Do that every time you clean and the wood rod will last you a long time