FWIW: before cold starting a Rotax 4-stroker, I was taught to check the oil level by opening the reservoir, then rotating the prop by hand until hearing from the reservoir a noise like flushing the loo, then apply the dipstick. But other pupils started the engine for a minute, then stopped it to check. Not sure which is best, likely it is the most troublesome...
When hand-turning the prop, it has to be done counterclockwise (as one looks at it) otherwise air might be sucked into the oil circuit. That's to say, if my dusty memory is to be trusted.