The strongest traditional shanks are probably Hazelnut with the bark either on or off. The bark is usually left on for two reasons, first is that it does look good with some heads, but another reason often is that it is quite labor intensive to remove the bark, and smooth up the shank. Bark on shanks requires almost no sanding. Most fruit wood water sprouts are quite good for shanks. They should be fairly straight, and the dimensions need to be right, about 5 feet long, large end: 7/8 inch and the small end: 1/2 inch or there abouts at the ends.
All should be left long enough to allow the ends to be cut off when dry to remove any checking. Cherry is good both with bark on or off. Apple is best bark off. Pear is very pretty light chocolate colored with the bark off but straightens poorly, Hawthorn is striking in its stark bone white, and if you are lucky, there will be deep purple veins at the tip, straightens poorly. Holly is wonderful but very heavy, also straightens poorly. If you can find Sassafras, or diamond willow of the right proportions they make a very beautiful stick. All must be dried for at least a year, and longer is better. They are straightened with heat, and steam, and green wood will not hold its position well.
I've found that although the tips I've gotten from Great Britain are the best, a good alternative is found at the shops that make hydraulic hoses for heavy machinery. The ferrules used there are available in 1 mm increments from very small to perhaps 20 or 30 mm. One end is slightly swedged open, and the other swedged slightly closed. I use a good tight press fit and leave 1/4 inch over the end, drill a small hole, fill the end with fast epoxy, and tap in a concrete nail flush "or close" to the end. This process makes a very durable tip.