Extending your delivery hose from say 10 Mtrs to 30 Mtrs, is there any discernible loss of pressure ? No
Using quarter inch hose as opposed to 3/8 hose, again what the difference performance wise ? Not with the size of machine you are using, it helps if its a shortish length just before your lance as it easier to handle
Quick release connects, any recommendations for a lubricant ? Just use water to rinse out any c r a p and then give it a squirt of wd40
Unloader return to tank...is it ok to just run it as is, full flow back to tank or is it a good idea to restrict it a little so the pump is not just running flat out ? Not sure exactly what you mean there mike? An unloader is a low pressure way of "unloading" the water when you are not using the lance. There should be no water "unloading" out of it when you have your trigger pulled