9003364 (the steam and hot water valve) is listed on a couple of sites as having a 1.3mm orifice. Several sites (including the one you have found) that list a single replacement part for both 9003364 and 9003435 list that part as having a 2.5mm orifice. Reneka specifying a smaller orifice for the water and steam outlet valves would make sense, as it should avoid any possibility of water draining from the steam boiler faster than it can refill.

All the original fit solenoid valves on my machines (I now have 2) were parker lucifer, so if yours are too, you might find some helpful information on their website. If you have the old valve, they have a reference code laser etched onto the edge of the flange, so you might be able to cross-refer that.

Must admit that before you posed the question it had never occurred to me that they were different. Having just re-built a Techno, I think I'll now check which valves I have fitted where.

I'll look when I get home. I can tell you the effect of the larger diameter on the tea dispenser -- the hot water floods out in a cloud of steam. There is definitely an advantage to the smaller diameter nozzle in that location. Will get back later.