Lizard Pit (Cunninghams Skink) to be precise!

[raycam01_au]

ok guys' looking for some advice, likes dislikes etc for my idea, i love the idea of an outdoor pit and currently cannot do that, so after buying my first reptile (Beautiful 6ft BHP boy) i was hooked, i have always kept fish so i had 2 nearly 8x4x2 foot Reln ponds i thought i would use to make an indoor lizard pit!
i have put a couple of piccies up of the pond juss for size reference etc, dont worry bout the bits n bobs inside it, juss using it as a holding tub right now
i hooked up a mock holder for the basking light, and attached it to a old Habistat dimming thermostat i had lying around, i will acutally be building up a slate and sandstone rock enclosure for the guys to bask on n chill.
now a couple of Q's if i may.
the garage they are in is not fully enclosed which i will ensure is done prior to putting lizards in but will still get alittle weather in (cold) etc.
Q

• will the basking light be sufficient for the Skinks (2 pair) its currently a 150wt Phillips spotty.
• what type of substrate would u use, i have access to any sands etc cheaply so this isnt an issue.
• do i leave the base as is smooth for ease of handling?
• i do like blue tongues as well, are they or would they be compatable in the same enclosure, maybe a pair?
• ummm any other things you guy's can add or assist with would be appreciated.

here are a couple of quick pics to give you an idea.

Thanks ray

 

[Damo1]

Would be good for both species as a pair