My DS had a really sensitive gag reflex...made for many a frustrating meal for Mommy (not so much for him
).
I actually had to work up to more solid food from pureed by just gradually making the food less pureed/smashed up. I'm remembering a meal I'd give him with carrot chunks in it...at first, I mashed the carrots until very smooth, then I mashed them less and less until he was able to handle chewing and swallowing the bite-size pieces without gagging. It took a while (like a couple of months).
And to take pressure off of yourself--I was given this advice on here--focus on just one meal a day to start amping up the texture. Then, as that meal falls into place, expand
It saved my sanity.
As for him actually touching the food whose textures he doesn't like, will he still eat them, or does he refuse flat out?