Hi, Tomas.  I'm very glad my suggestion was of some use to you.  My left handed slinging is extremely humorous.  I guess if I did it more I could get used to slinging that way.  In that I usually sling with my two Huskies in tow I have to be careful and not take too many chances.

I felt like a 3 yr old when I tried at first. I can now sling lefty to a degree... not well though

Maybe we can all tape ourselves slinging off-handed and remake this video

Hehe we should totally make that video! I know I would have some funny material for it lol anybody else game?
So nobody is an ambidextrous slinger? If not I'll be the first

I've been slinging with my left for a few years now.

I no longer think of it as my "weak side."  I now see my left as my "foundation" side while my right is my "active" side.  Or My left is my grandfather side and my right is my impulsive young warrior side.

Think of all the work the left does.  When throwing right handed, the left foot plants and gives the foundation.  When shooting a gun or bow, the left actually does most of the work stabilizing.  I found that my right hand does not like to do the supportive work.  It's like the 5 year old kid brother jumping up and down saying, "I wanna do it!  I wanna do it!"

With slinging with my left, I found my accuracy developed pretty quickly although my power hasn't.  Switching has lead me to respect my body a little more because I've come to understand it.  I now cringe when I hear people almost curse their left side as "weak," "broken," "wrong,"etc.

BTW one of the best archers at my archery club was decent as a righty.  He injured his shoulder and had to shoot as a lefty.  He had to drop some pounds on the draw but his injury was a blessing in a way. 

Have fun.  I believe switching hands opens up new pathways in the brain.

Thanks for the input RJB, somehow I still seem to be hitting things do I'm going to keep at it!
I'll have to add a video soon