I don't what size your PSK is, but with most such kits, some of the items (first aid, lights, matches, tinder, etc.) obviously need to be in a watertight container and some (knife, multitool, fresnel lens, signal mirrors, etc.) do not. You can structure your kit to protect those things needing it in the small Witz containers or smaller otterboxes and carry the containers in a pouch with the other items. That way, things that need sealing are sealed and those that don't are not, but all are accessible without compromising waterproof seal.