Thank you guys for the replies.
I totally understand your points, and you are right. I had the pre-feeling something was not completely right when I did them, and again, a post on this forum is putting me back on the right track
I will definitely try to make new ones. It will have the other advantage for me to accurately chose the height and get rid of these small 15mm steel extensions cylinders I built and I'm not found of either.
Keep you posted.
Thanks again.