Ackie questions

[SerpentSteve]

I have recently considered acquiring a pair (or a trio of babies if I can't find a sexed pair) of red ackies. But I like to have a comfortable amount of knowledge of any animal before I get it so I have a few questions.

1) Who are some reputable, trustworthy breeders?
2) I have seen the "coffee table vivs" on Cages By Design and a family member of mine happens to be a carpenter, so if I had him build one would a 4ftx4ftx30" be large enough for a pair/trio? Or should I maybe just use a large terrarium?
3) What age do they mature and HEALTHILY breed at? I've seen anything from just under a year to over 2 years on care sheets so I want a more definitive answer.
4) What is the best substrate that won't cave in when they burrow? Something that would hold up for the burrows to be continually used?
5) Not really a care question just curiosity, do ackies tripod like other monitors?

Thanks,
Steve