Got the I.R. working with drops, put a short piece of drinking straw over the phototransistor held in place with blue tack then covered the end of the straw with blue tack and poked a hole in with a piece of wire. Seems it needs a lot less light to trigger from a water drop than my finger (although my finger is supposed to be 80% water!). Tested this evening but seems less reliable than just using the timers, more tinkering required.
Started off just using 6mm tube but I have read the solenoid nozzle size is quite important so i made 2 & 3mm I.D. nozzles today and so far prefer the 3mm.
Got some balloons today so the sound trigger will be tested soon.