I'm with Madgirl, I've close on 1000hrs of 'conventional' flying and actually found weightshiffts fairly straight forward to fly.
The 'trick' is much like left and right hand, stick and yoke - get the right mental picture and it just slots in. But on the ground I did have to think!
So I do not believe it is that difficult to 'convert'. The trick is to find the right mental picture, in my case to 'fly the wing', knowing that it is about angle of attack and roll not about stick or yoke movements.
And it is great fun - although turbulence is hard work!