Just been out to the garage for these photos,this is where mine is mounted,I can reach it quite easily on a quiet road and keep the button pressed down for about 10 seconds in the summer, and about 20 seconds in the winter when the oil is quite thick.I have tried many oils over the years and have found that cheap 10w/30 is a good all year round lubricant.
Just make sure that the button returns after use,as after a few years road dirt can get under the button and make it stick, it is easily remedied by pulling the button off the plunger and cleaning inside it.A better solution is to put a black baby sock over it to keep the road muck off it.