When working on valve bodies for the first time ziplock bags can be your friend. Put each valve and spring in a bag and mark it with a pen as to what valve it is. It is easy to become confused and get things mixed up otherwise.
Make sure all valves move smooth in the bores without oil. They should fall out of the bores under their own weight. Also after tightening valve body bolts check to make sure the valves work smoothly. Sometimes tightening the valve body bolts can distort the bores and stick a valve. C4 valve bodies usually don't have this problem, but best to check.
Also do not tighten the end plates of the valve body until the valve body is bolted together. The reason is tightening the end plates first can cause leaks due to improper seating of the valve body halves which may cause internal leaks in the valve body.
