To give some more information regarding the color chart i made, i will add some more photo's to explain wich colors where used.
First, the color chart, using 2 base colors (XF-78 and XF-59) and 4 oil colors ( Transparant oxide yellow, Burnt umber, Raw umber and Van Dycke brow)

1). two base colors XF-59 and XF-78 and oil color Transparant oxide yellow.

2). two base colors XF-59 and XF-78 and oil color Burnt Umber.

3). two base colors XF-59 and XF-78 and oil color Raw Umber.

4). two base colors XF-59 and XF-78 and oil color Van Dycke brown

Like you see, this will give you in total 8 different wood-grain colors.
Greetz
Danny