Would it be better to use the Wilton directions for RI or add a little more water to it so that its smoother and easier to pipe?

Would the extra water make the snowflakes weaker?

Yes adding extra liquid would weaken the royal
It sounds like maybe your are overbeating the royal in the 1st place.
You do need to beat it about 7 minutes or it won't hold it's shape but if it is hard to pipe w/I think it's over done.
When making the royal if you use warm water you won't have to beat it as long. In my KA it usually only takes like 3 minutes when I use warm water. If using a hand-held then it should be aobut 6-10 minutes.

What would underbeating it cause? I'd hate to waste another batch!