Tungsten dart barrel surface is covered by knurling or rings for a safe grip on the dart. Again there is a vast selection of different surface shapes, and combinations of them. There is the possibility of a plain surface (which beginners are usually unhappy with). It can't be said which variations are the best ones. Choose what suits you, what feels good and what you think you can handle.
There is only one thing you should avoid: painted surfaces. Paint might look good, but usually it makes the dart only more slippery.
We appreciate very much to receive your particular designs, and always try all out to meet any specific requirements. The motto for our company is that, there never be minimum order, but any one could bring to us the most potential buyer.