I mentioned in another thread that I had made a simple manometer that worked really well in balancing the dellortos on my S2 spider. I came across it today while having a sort out so took a picture in case it would be useful to anybody wanting to make a similar one. Parts list: plank of wood, plastic pipe, cable clips, 2-stroke oil. Simple but effective and I balanced the barrels (with the air bleed screw) much more accurately than possible with a gauge. Just be careful to attach both ends to the vacuum ports before starting the engine, and balance pairs of cylinders at a time.