I use a lanyard as long as the weather is warm. Much cooler than a vest in summer. Clip at bottom to attach to shirt a good idea.

One zinger-like attachment is placed high on left side of cord, and is used to carry cross-lock tweezers for getting #18-26 midges out of C&F box. I take the fly out of the tweezers with a small Ty-Rite spinner on right side, thread and knot it, then remove tag end with clippers also carried on right side. All this can be done easily with rod tucked under arm.

There are leftover clips on lanyard for carrying shot dispenser, floatant, tippet material, small box for used flies, etc....tho I usually carry most of this stuff in a belt pouch that also accommodates two C&F fly boxes. I hang my license off the length-adjustment cord at the top of the lanyard, behind the neck.

This may read complicated, but in practice is very efficient. Lots of variations possible, based on your preferences.