I have to do my sisters wedding cake and she wants a 6 tier construction with spaces in between each tier. Does anyone know which would hold up better the tall tier by Wilton or just using the seperator plates with 6 inch pillars that penatrate through the bottom cake so there is a 2 inch gap? I have never did a cake with spaces in between the tiers so any help would be appreciated. Thanks in advance!

The Wilton Crystal Clear set is a lot better. Pillars can be bought longer, or cut with a saw to desired length.

...... which would hold up better the tall tier by Wilton or just using the seperator plates with 6 inch pillars that penatrate through the bottom cake so there is a 2 inch gap?......

That tall tier set up is not the best choice.
I much prefer using push-in pillars. The only ones I do NOT recommend are the very pointed clear crystal pillars. Get ones that are more blunt on the end that touches the board. If you look at the different pillars you will see what I'm talking about.