I start my CT thru hike June 10 and still not sure on my shelter choice. I'm between my Sublite Tyvek and 8x10 sil tarp...

I like the Sublite a lot, but miss the views that a tarp allows. I know many have raised concerns about the Sublite's water resistance, but I've read enough accounts of it standing up to some pretty heavy rain that I'm not much worried about it. I'm familiar with monsoon storms here in NM...heavy but short downpours followed by clear skies. I assume it's similar in CO?

As for the tarp...my dog is coming with me (50lb border collie), so the extra space would be nice. She walks into every mud puddle she can find so being able to put some space between us is helpful. The question is, what's the bug situation going to look like? Do I need bug protection to supplement the tarp?

Thanks!

The conditions are pretty much the same all over the southwest in regards to weather, storms, bugs and water.
The rain in CO is very similar to what you are familiar with in NM, the short PM monsoon.
There really aren't many bugs unless you insist on sleeping 10' from slow-moving water. I wouldn't think a bug net is required.
It's pretty easy to get above treeline here in CO,and the average elevation of the CT is near 10k' ASL, so if you can pitch a tarp with out trees, I think you'll be fine. Otherwise, I'd look really hard at the sublite.