This is an absolute loaded question for a bunch of reasons. I've spent the last 2 years focused on field testing my strikers to come up with the best design that suits my calls specifically. Everything that I say here is just my own personal opinion based on what I have learned.
First, I generally choose the species of wood for my strikers based on the friction surface. For my calls, the softer the friction surface, the softer the wood for the striker. Slate is the softest so I can use anything like black walnut, hickory or purple heart. As you move up through ceramic, glass, crystal and the metals, I look for harder woods. You can Google the Janka hardness scale to see what the hardness levels of wood are.
The harder woods over 3000 on the Janka scale generally produce a deeper tone and van be played on any of the friction surfaces in my calls. They also take away the squeek that you may encounter.
Other important factors are the profile of the striker tip whether its a standard tip, mushroom tip and the precise degree of the tip. The thickness of the peg itself plays a vital role in the performance of the striker as well as the sound that it produces.
With all of that said, my Evolution striker in tulipwood could sound and play differently than a tulipwood striker from a different call maker.
I would suggest owning about a dozen different strikers, as many as you can from the same call maker for the sake of consistency. Some of my personal favorites are: black walnut, hickory, yellow heart, purple heart, wenge, Caribbean rose wood, black locust, pie and lignum vitae.
