I'll add to AP's suggestion. If you use the slot board, buy the metal slot inserts. If you hang something heavier than maybe ten pounds on a rod the clip can pull thru the shot in the board. The metal insert allows you to hang some serious weight on slot board. Some of the slots where I have shelving hung have the inserts. The slots with the lead molds do not have the inserts.
Like the metal pegboard, slot board allows one to quickly and easily change things around to custom fit what you want to hang. It's amazing how little wasted space there is using slot board.
And no, these are not the only lead molds I have. I have several vintage Do-It molds from when they were made in a garage, I believe. I have other molds from other makers that I've collected since the mid 1970's. Maybe 80 molds total i addition to what is in the picture. The ones in the picture I use frequently, the others I don't use any more.