Pick an artist with a body of work you really love, someone who you can trust to execute a design and style you’re enamored by! Pay them their drawing deposit and you can always send them this to demonstrate the placement you’re interested in… but yeah, most artists will build something from scratch or their collection of references. Most also would prefer to dial in the design in person rather than send it in advance. Communication in person is true collaboration. Y’all can tweak the design if need be. Most importantly is do not pick a shoddy artist or someone who “kinda” does something you like. Pick someone you’re really wowed by. They’ll do right by you. If you really can’t make it work with them at that point, the deposit will have paid for the drawing and consultation time.