I'm just getting ready to plumb the retracts and doors , got a few questions, hope to avoid some of the issues that others have encountered. I've looked at all the electronic valve options and I think I'm going to go with a simple mechanical UP3 valve for gear and doors (any issues with that?)

Also, looks like the air cylinders on the mains will not accept 3mm air line, better suited to 4mm. Most (if not all) valves on the market seem to accept 3mm lines. Are you fellows simply stepping down the size of your lines at the air cylinder with a 4mm to 3mm reducer or is there a way to plumb the whole system with 4mm lines?

Haven't bought any of the hardware for the air system yet so, I'm open to better suggestions at this time.

TIA

Mike