I don't know about tinder for a bow drill, I use a ferrocerium rod fire steel? & For Tinder I like to use:~
Kapok & Maya dust. Kapok is a fluffy yellowish fibre which surrounds the seed pods of the Ceiba pentandra tree, the (national emblem of Guatemala)
Kapok_seeds
Kapok is the most used common name for the tree.
Adult trees produce several hundred 15cm (6in) seed pods.
The fluffy, yellowish fibre (Kapok) is a mix of lignin and cellulose. The fibre is light, resistant to water & very flammable. It will light very easily from the flurry of sparks produced when you strike your fire steel.
Maya sticks (Fatwood) for kindling
Because of the flammability of terpene in fatwood it is prized as kindling for use in starting fires. It is derived from the heartwood of pine trees. This resin-impregnated heartwood becomes hard and rot-resistant. The stump (and tap root) left in the ground after a tree has fallen or has been cut is an excellent source of fatwood. it lights quickly even when wet, is very wind resistant, and burns hot enough to light larger pieces of wood.
by shaving small curls from a small piece of fatwood you can create tinder A.K.A . Maya dust which can be used to light other larger tinder/kindling, such as fatwood,
This should wet your appetite :~ A brilliant site for bushcraft related pyrotechnics & bushcraft essentials
http://www.sharkdesigns.co.uk/home_pages/1_fire_online_store.html
http://www.beaverbushcraft.co.uk/ourshop/prod_3485329-Mark-Hordons-The-Fire-Buddy.html