Had another go tonight, with more success.
Went to Joanne's Fabrics again and picked up thinner thread. I took a different color reference with me - found this image online:
I realized that the dark blue has some purple in it, and the light blue is more of a green oceanic blue. It actually looks, out of context, like Laguna Seca Blue to me. I bought these spools and used the first, third, and fifth ones. The thread I used is:
Gutermann SewAll thread #263 "Geneva Blue"
#610 "Mystic Blue"
#406 "Tiger Lily"
This thread is significantly thinner than what I tried initially and I think it's a better look. It's also easier to sew. Using the same pattern as described in my last post I went through and did the red and light blue.
Zig-zagged them with the dark blue. Go through every other loop on each side, very simple. If you can lace your shoes, you can do this.
Finished product - only one of the three boot seams, but representative! Didn't bother to tighten down the thread at the ends either since this is my practice boot.
There you have it! Total cost of supplies is $2/spool plus a pack of needles, so maybe $10. Super easy and a really nice finished result. Go spend the $350 you didn't send IND on something else for your car!