It is harder and messier than your imagination though.

宁可少加点也别加多了..NONONO...it is actually better to overfill a little...than under fill..cause when you overfill and the car reaches the right temp range, it will trickle out from the fill hole.(think about it.------------that means you could never really overfill it above the hole!!!!)...until to the right amount...make sure you have towels wrapped around the oil bottles so when you spill some it doesn't get slippery and ruin your whole job. Don't ask me why i say so. ;o). This is probably toughest multi-tasking job you will like to encounter when working on a car, and it will often result in a several attempts over some time until it's done right...

it is easier to do the job while the sump temp is rising from lower 20C on the way up than waiting the sump temp is right around 35~45 and start doing it. You overfill it until it reaches the right temp and it will trickle out by itself----that means you have more time to do fill job and less likely become panic when the temp window is only about 3~4 mins.at 35~45 C range....you only need to use one hand to hold the thermal scanner to read the temp and the other hand hold the fill plug to ready to pounce on the hole to seal it properly once it started trickling...

I have given all tips I can think of when doing it myself. There will be twists and turns per your own course of action as you will find out when actually doing it. But you have to do it to find out.