This IS an engine question and MAY belong somewhere else, but being a general question, I thought it might fit here best. I've changed the gear oil in my 60 bigfoot and my 30 'rude. Both times it was messy as the nozzle of the bottle doesn't reach into the filler hole. The upper and lower anti-ventilation plates get in the way. A short piece of 1/4" hose helps. Is there a better way? Secondly, how do you know how much to put in? Pulling out the hose after every squirt to check is a PITA.