I find two problems when using commercial dowels for furniture joinery. The first is they are rarely the exact size as advertised. The second is that for exposed joints the select of specialty wood dowels is limited and quite expensive. My solution is to make my own dowels. It is done by pounding a square stick through a series gradually shrinking holes in a steel plate. A benefit is that the hole in the plate not only shaves off the corners but it also slightly compresses the wood. This means that in the presents of glue these dowels will slowly swell a bit and grab on to the hole in is inserted into. They are easy to make if you follow they three steps.

Step 1: Cut Square Sticks

Saw straight grained lumber of you choice into sticks, a bit wider the 3/8" square. Then slightly sharpen one end.

Step 2: Make a Hole Die

Take a short strip of 1/4" thick steel and drill nine holes with the following diameters; 1/2", 31/64", 15/32", 29/64", 7/16", 27/64", 13/32", 25/64", and 3/8". Use any old steel you can find and don't worry about hardening it. It will get work hardened by continual use.

Step 3: Pound Dowel Into Shape

Start by pounding the square stick through the largest hole, twice. (I pound through a hole in my bench.) Then move down to the next smallest hole and again pound through twice. Continue this process until you have used all the holes. The second photo shows the dowel partway through the process while the third photo shows the completed dowel.

Afterthought
Now that you can have dowels of any type of wood, be creative. If you are making a special piece of furniture for a friend or family, make the exposed dowels from a piece of wood that has memories connected to it. (Like the piece of olive wood your Mother got on her visit to the Holy Land.)