im not that far in the game so i couldnt answer several of these but ill try!
1. 180G, that just seems like a perfect size for me
2. id like to say LEDs, but it seems for larger tanks MH
is the way to go, so probably 3 MH
with maybe some LEDs for actinic or just good ol T5s
3. for skimming id like to over skim most likely, because if i had this setup id do an octopus/cuttlefish tank, then a reef.
4. probably like a 75 or so refuge, keep a peacock mantis in there !
5. may 3-4 koralias
6. dont know enough to say
as for extras i have no clue except getting a RR tank, thats a must. id be much too scared to drill any tank
thanks mdaniel. this was actually fun to think about!