Fluorescent vs. Metal Halide Side Lighting

I'm going to change up my lighting scheme with this new batch, and I wanted to get everyone's input. Last grow, I flowered four plants in a 4x4 area with a 1000W HPS and two T5-HO fixtures (4-bulb, 4-foot = 20k lumens/each) for side lighting. The plants did well, but I noticed that the buds nearest the T5's had the best looking trichomes and healthiest leaves. HPS has a very limited spectrum, and the T5's gave the plants something extra. Fluorescent light doesn't penetrate much more than 12", so the buds in the middle of the cluster received high intensity 2000K spectrum from the HPS but virtually nothing from the 6400K T5's, and those buds did not turn out as well. Many growers on this forum use both HPS and metal halide for flowering and swear that their quality is better than HPS alone, so I'm considering a couple of 400W MH fixtures to replace the T5's.

Questions:
Do you think that the 400W MH will penetrate further into the canopy than the T5's? Of the many color spectrums offered in MH bulbs, which do you think would best complement the HPS (3000K, 6500K, 7200K, 10,000K)? Is a 600W HPS plus two 400W MH better than a 1000W HPS plus two 216W T5's (considering the power bill)? Any suggestions would be appreciated.

The 400W MH will definitely penetrate better than the T-5. The question should be how would you position a MH for side light in a 4x4, AND how would you cool 600w and 400w efficiently in that small space. Id forget about the 400W MH for side lighting. Use it for a small veg tent and grow perpetual.
In a 4x4 tent the 1000W is a waste, IMO, use the 600W with t-5 side lighting. How would you place a 400W MH for side light? Id be scared to light my plants on fire.
With 4 plants in a 4x4 with a HID fixture AND side lighting you should be able to grow some pretty good sized plants. Top them 3 or 4 times, veg for 6 weeks min, lollipop them, and youll get a huge harvest.
I have a 4x4 tent, 600W HID that takes HPS and MH. Dimmable from 250/400/600w. I use t5 for side light and sometimes a CFL here and there. I grow 6-8 plants usually and i put them in 6 gallon fabric bags. Advanced Nutrients for nutes. After a year of growing, i am now getting the coveted 1gram per watt harvest.

Thanks for the feedback. I should have mentioned that the 4x4 area is only the amount of space that the plants use. The room is 9x10 with 9 foot ceilings. With a circulation fan and and a beefy exhaust blower, I have no problem keeping the plants cool. I used the T5's on the sides, with the fixtures set slightly above the top of the canopy and angled slightly down. This was the most evenly distributed supplementary light I could achieve with those fixtures. The 400W MH fixtures would still be off to the sides, but fully above the canopy, a safe distance from the plants. I had also considered four T5's, which would offer much better coverage, but I think MH would give more bang for the buck.

1g/watt is spectacular. I'm just under 0.5g/watt, but I'm more concerned with quality and trichome production than with yield, and I'm growing a fairly low-yielding variety (Girl Scout Cookies). Where did you get your 250/400/600 ballast? I've been looking for one for days, and I can only find ones that dim by percentages of 75% and 50% (worthless if you want to actually dim with the proper bulb).