Questions on fluorescent lights

I am beginning to collect some information in order to decide if and how to
increase the lighting levels in my 180 gal tank. Currently, I have two 36"
dual light hoods, driven by an IceCap VHO ballast. I realize there are more
efficient and way cheaper alternatives available, but I have to say that the
IceCap was very easy to wire with the provided harness (I am almost afraid
of electricity!), it runs really very cool (the lamps are hot though), and I
feel safer knowing there is a built-in fuse and automatic shut-off system
(is this a real added safety feature, or the fuse on the main electrical
circuit would basically do the job as good? I often go away, and if the
whole electrical circuit shuts off, I am going to loose all the fish, while
if only the ballast shuts off, filters and heaters should keep going). 

In order to better understand the alternatives available, I would like to
know if anyone can answer the following questions:

1) Ice Cap ballasts can run VHO, HO or NO bulbs, even mixed in the same
fixture. What are the concequences of using a NO bulb with it? Shorter bulb
life? Decreased efficiency? Decreased lumen output compared to the VHO bulb?

2) In general, how frequently should VHO bulbs be changed, and how
frequently should NO bulbs driven by VHO ballasts be changed? The
manufacturer recommended 1 year for VHO and 6 months for NO. 

3) Currently the new T-8 high efficiency tubes (particularly for
full-spectrum outputs in the 36" size), are not easy to find at the retail
level. Can the new high efficiency ballasts drive normal fluorescent tubes?
Is it reasonable to expect that they will become more easily available in
the near future?

4) Would an IceCap VHO ballast drive the new high efficiency T-8 bulbs? Any
consequence in terms of efficiency, lumen output and expected bulb lifetime?

5) On a by-lumen basis, are there data available comparing the efficiency of
an IceCap VHO versus the new T-8 tubes?

Thanks to all those that will provide suggestions.

dionigi.maladorno at roche_com