I had some things to add but got very busy at work. All the above advise is great, we got some lizard guys here eh? With crickets I had far better luck ordering in bulk online and keeping them. They're not as easy as mealworms to breed but its not difficult. One note from above, skip the water bowl in the cricket tank. They drown incredibly easy, I used the flukes food and sliced potatoes and they never had an issue getting sufficient moisture. Large (30ish) gallon Rubbermaid tanks work great for housing. We would smear a ring of Vaseline along the inside a few inches from the top and never had any escape not even using a lid. Egg crate is their friend for increased surface area.
On the incubator, my brother in law and I were heavily involved breeding leopard geckos, panther and Jackson chameleons, and ball pythons so we went in on a roughly $400 unit that was superb. I can get the brand name if your interested. Either unit you linked will work, I'd spring for the exo terra, I've never used one but a guy on our old forum swore by them, he had three.
I totally support your idea not to use a breeding rack. I actually still own one but its the least possible humane way to keep an interactive reptile like a lizard. I was more comfortable with using it with my snakes but even that isn't great.
On the D3 thing, absolutely great that your using it, that's often overlooked and the poor geckos die a long slow death. The topic of lizards and uvb is still somewhat debated but its became a lot clearer in the last decade. Many lizards, especially monitors absolutely require uvb, d3 doesn't help, but some still believe leopard geckos can survive off d3 alone. Key word, survive. Try a little test I conducted, keep him on d3 a while, then go get a uvb just to see how he reacts. If it goes like my experience you'll never take it off. Many of the breeders (big time show breeders, we were all repticon season table holders) that I dealt with agreed, uvb is the way to go unless you have so many you can't physically provide it to them all, hence the use of d3.
Wow, didn't mean to get that wordy, hope some of it helps.