As Dave stated: whole will store best. It is very tempting to grind what you will use as a powder form prior to storage due to the fact that powders need far less space than whole, sliced, diced, etc. Also, you have less clean-up time and cross-over of flavors from your grinder when you do one item at a time and in larger batches...there are lots of reasons why you would want to go straight from dried to powder...try to resist that urge. The more you break it down the faster it loses it's flavor, just like spices and herbs. If you grind to powder form, then store, you lose a lot of potential flavor. Also, storing in glass with metal lids (canning jars are great) instead of plastic is best. Plastic allows oxygen to pass through into the contents...rancidity (when oils/fats are present) will eventually be the end result (I have found numerous unopened plastic containers of garlic, etc that were rancid). Glass and metal prevent the passage of oxygen from the outside air. If you have canning jars and a vacuum kit (available for reg & wide mouth) you have a great storage option. There are additional means which provide good longer storage as well. Mylar bags with oxygen scavengers are a popular option, though they must be run through a heat-sealer. As long as you have a proper container, remove the oxygen via scavengers or vacuum, and seal the container to keep it from re-entering, you will have a viable long-term storage for dry goods.
As for smoking, you can slice in half, or just make a slit down the side to allow moisture to escape during smoking. If cut completely open, they will smoke faster, and dry slightly faster as well. Some folks like to smoke and dry whole to keep the seeds inside...personal preference. Keeping temps lower helps preserve the peppers by not getting so hot that the flavors and nutrients are destroyed. Recommended drying temp for most veggies and fruits is 135*F...I've gone lower for longer time after the initial 135* just to enhance the quality of the finished product. You can smoke, then dehydrate until dry, or just leave in the smoker at low temp until dry. Your smoker needs a fair amount of draft/ventilation during drying to allow the water vapor to escape or your drying time will be excessive. What should take 12-18 hours in a
dehydrator could take 2+ times longer in a smoker with inadequate ventilation.
It's been a while since I smoked/dried any peppers...this reminds me, I've been slacking too much, lately...LOL!!!
Enjoy your smoked peppers!!!
Eric