Those IR "IPS" units should work well. Some 555 timing and logic circuits can be very tempermental. One lister on this forum made a 555 toggling some p-ch. mosfets to alternately select high or low beam headlights on his motor home. Without touching anything, lights would just switch at random. In the end, he replaced the 555 circuit with discrete components. Be sure the 555's have very stable clean power sources. They should have their own automotive rated regulator. National makes a nice one, but I don't recall the part number.