There’s two basic handle types to choose from: Japanese or Western. The photo above shows the exact same blade with each of the handle types. The Japanese handles are straight and fairly consistent in width from end to end. The Western type is generally narrower where the index and pinky fingers go with a palm swell in the middle.
The Western style seems to be more comfortable and ergonomic. But in reality you don’t always grip a knife like a golf club or hammer. So those contours aren’t that important.
My Western style handles use a full tang construction. In other words the blade steel extends thru the entire handle with the handle ‘slabs’ epoxied on each side.
I should note that I use a special epoxy that will last forever. It’s actually used in the construction of airplanes!
Japanese style handles use a hidden tang. The blade steel is narrower than the handle and hidden inside the wood.
The handle cross section can be oval or octagonal. That choice is purely aesthetics and doesn’t effect the use.
Which do you choose? It is entirely a personal preference. Personally, I’ve been enjoying using a Japanese style handle. It supports many grip types and looks pretty cool.
However, your material choice might lock you into one or the other. More on that in the next step…