Imperial to metric olive - Which way?

[Harvest Fields]

I've always found them to be so close in size that the fittings are interchangeable on the 15mm - 1/2". The 22mm - 3/4" are way out so need an adapter but you have problems with the 15 to imperial?

Never had one that went on properly, had to use the correct fitting

 

[Welder]

I've always found them to be so close in size that the fittings are interchangeable on the 15mm - 1/2". The 22mm - 3/4" are way out so need an adapter but you have problems with the 15 to imperial?

My experience is as yours Stig.
My take on the images is top. Why? Because the longer taper is far more accommodating of dia. Look at the short end. It is perfectly matched with the olive.
Just my two penneth 😉