Setting up my first SW 90g + lighting

[Winters]

Hello! New member here.
I am in the process of getting my first reef aquarium going. It is 90g (48" x 18" x 24") with a 20g sump, protein skimmer, RO/DI water, 40lbs live rock (for starting Nitration cycle), and about 1.5" of sugar grain size aragonite sand for substrate. I plan to (eventually) keep mainly soft and some stony corals and a medium number of fish and invertebrates.

Some photographs are here: http://www.canreef.com/photopost/sho...00&ppuser=1497

It's now been cycling for about 5 days. Ammonia and Nitrite readings are still minimal, so the cycle is just starting or so it seems. Live rock seems to have had a fair bit of die off, if not a complete die off. Is something still alive in this live rock? Any ideas? I think I've killed all the worms and things.

I do have a question.. about lighting this aquarium. The aquarium comes with a (very pretty) wooden hood/canopy. (As pictured at the link above) I would like to install lights inside the canopy but don't know how to do it and what to install in there. I would like the shimmering effect caused by MH's (and HQI's) but I'm concerned about overheating especially in a canopy such as this, plus I don't want to install a chiller. I also want to keep energy usage as low as I can manage. Any ideas?

I did some research and found a couple of items that may work:

There is a 48" CoralLife AqualightPro fixture that I can install with two HQIs and two actinic PCs . Here is the link for this:
http://www.marineandreef.com/shoppro...aqualight.html
Is this a good idea for this setup? Surely would be easier. Not sure how it would live inside the hood though and also not overheat.

There is also a Hamilton Lighting 2x175W MH + 2x96W Actinic PCs retrofit available. Would this be better? Here is the link:
http://www.marineandreef.com/shoppro...175_Retro.html

I have also found a kit for putting in 4 VHO tubes of 110Watts each. (So this should be cooler but no shimering) Can someone comment on this? Will this be a good idea? I mean.. a VHO only setup.. would this look alright? Here is the link:
http://www.marineandreef.com/shoppro...ting_kits.html

And how IS HQI different from MH? I get a feeling that HQIs are somehow better than MHs. True?

Also.. since this will mean lighting installed inside the canopy, will I need a glass or plastic screen between the light and the water? Or can I skip that? Or does it depend on if I get MH/HQIs or just VHOs?

Need some advice desperately!!
Help!
_______________________________________
Imran, in Edmonton/Ardrossan, AB