toying with the idea of Leos

[Stewart_Reptiles]

1. Are mealworms an acceptable staple food source, with occasional roaches or other worms for variety? (I raise mealworms anyway and have read that they can eat all life stages)

Perfect food for all ages and easy to produce yourself.

I have also read where some people use repashy "grub pie" for geckos as a supplemental food but I'm not sure this of for leos vs arboreal species like the fruit based gel foods.

I tried some mix for Leo they never went for it, they like the hunt

2. Is there such a thing as too big of a cage for an adult? I like the idea of something the size of a T10 (48x24x15) for lots of customization - multiple hides, multiple substrates, cage decor, etc

In something that big I would have more than one I would have a haremm, problem is you can only do that with either all females or 1 male several females but all must be mature and big enough as egg binding is an issue.

3. I understand that young geckos need far less space to reduce stress, but how fast do they grow? Can you start with a 10-20gal footprint terrarium then move to something bigger?

Depends how good they eat usually people start small and house 1 adult in a 20 gallons floor space which is more than enough for a single individual.

4. Being nocturnal I assume that a CHE would be best, but do they need visible light to know where to bask when needed? Probably a silly question

Not necessarily I have use UTH with mine, not a fan of bulbs that can break.

5. Can sphagnum moss be used safely for moist hide substrate?

Yes

6. I've read everything from tile, repti-carpet, and paper-towels as substrate plus occasionally eco-earth (dried out) for digging enrichment. Is there a 'best' or is it what you feel like cleaning up?

unprincipled news paper for quick cleaning is best

7. Is there a big difference in personality / health between genders? Any worry of egg-binding in non-breeding females?

No and it can happen they can produce eggs without the presence of a male.

8. Most I've seen are sold young, some tiny some a few inches - any pros/cons with purchase age?

Raising a baby is fun and they will get used to you, buying an adult can be more of an issue they might be more aggressive and bite.

9. As for supplements I've read that its is suggested to leave the calcium+d3 down in the cage at all times, as well as dust insects with both that and vitamin powder- but the recommended supplement schedules are all over the place from every feeding to once a week or less. Is vitamin A toxicity something common to them? I have not had to supplement a reptile since my iguana 15 years ago lol.

I have always kept a small dish of calcium with D3 vitamins and always dusted insect and most people do.

10. In the winter my house is 20-40% humidity, but in the summer that can be as high as 50-65% just in the house - will the ambient high humidity in the summer cause issues? I can add humidity for shed when needed, removing it is another story

Your leo will be fine

My ideal habitat would have a lot of natural rock, slate tiles, homemade grout structures, and easily removable areas of repti-carpet for quick clean up. Possibly a removable section of eco-earth for digging that was opposite of the feeding area, unless they will just eat it. Sorry for the word wall ;/

Repti carpet is great until your gecko tear up a toe because it get caught in it, I do not recommend it and I would stay away from anything that can cause impaction.