Every tank can be different; many do not follow the "norm." But there are some things on which all experienced planted tank aquarists do agree (yes, a few
One of these is that actinic light is no good. Plants often manage to stay alive under this light, but I guess they do not thrive. I have never tried it, I wouldn't, so I can only offer what those who are trained botanists (some of them are) and experienced planted tank folks write. Another comment is that it can cause algae problems.
If you read my article you will have read the bit on balance between light and the 17 nutrients. Only when these are available will plants photosynthesize (grow). If the light is somehow inadequate, plants stop growing, and at that point algae will take advantage because it can use any type of light, and there will likely be plenty of nutrients available.
Having said that, you may have a tank that has not seen this--yet. I wouldn't risk it. Sometimes algae is difficult to control and eradicate naturally, and "naturally' is absolutely the only method to ever use in controlling algae. And light is almost always the aspect that does it.
I can understand the colour accentuation bit; 25 years ago I used Grolux tubes, everyone did, they were the plant light. They cast a purplish hue to the tank, and the reds and blues on fishes were brilliant. I was out of the hobby actively for a few years, moving around too much, and when I got back in some 15 years ago, Grolux was no longer "it" but full spectrum was--and still is because frankly there is nothing better. It replicates the sun at mid-day. The blue and red that plants need--and they need both to photosynthesize fully (the absence of red is probably one significant issue with actinic)--is there, plus green to balance for a true rendition of fish and plant colours. And much as I liked the Grolux, I would never go back to that now, having lived with full spectrum. The "Aqua-Glo" and "Flora-Glo" or similar types of tubes are today's Grolux, and aside from the purplish hue they are also significantly less intense in light.
What I use on my large tanks is a combo of one full spectrum and one col white equivalent. Scientific studies have proven that aquatic plants grow best under this combination. Cool white is higher in blue (but not as much as actinic). On my 115g for instance, I have one 6700K full spectrum [Life-Glo 2 as it happens] and one 11,000K Ultra Daylight made by Lightning Rod. There is clearly a cool ("bluish") hue to the tank, but not sufficient to distort the other colours. The plants are happy (obviously from their growth) and the light is not "bright" because of the blue emphasis. I have a similar arrangement on my 90g, one full spectrum 6700K [also a Life-Glo 2] and one Reef Sun put out by ZooMed which is a combo of full spectrum and actinic. This has so far worked, though to be honest the same plant species do not grow as well in this tank as in the 115g, and considering that the light intensity is slightly less in the 115g due to the larger volume with the same two 48-inch tubes, this may be telling. Anyway, this was an experiment with this tube, and I want to give it due time before I pronounce judgment. It was the closest thing I could get to the lightning Rod which for some reason I can't find locally.
Metal halide's big problem is heat, plus cost to operate. And considering your low-tech setup, and the plant species, I would not go down that road when T8 fluorescent largely eliminates those two issues, plus provides what many deem near-perfect light.
The other issue with 4 tubes is simply one of too much light, even though half may be wasted on the plants. Algae as I mentioned. But the fish must be considered. Forest fish of the type most planted tank aquarists maintain in planted tanks are all with very few exceptions from very dimly-lit streams and ponds in the tropics. Rarely do these fish ever see the direct sun, or if they do, they avoid it by remaining in the shade of floating plants, overhanging vegetation, etc. These fish will look better in colour under less light, and they will be less stressed which means in better health. And this brings me to T5. Most T5 is HO (high output) which is considerably more intense (brighter) light than T8 or T5 NO (normal output, which is basically equivalent to T8]. Given the choice in type of tubes with T8, I personally would not bother with T5 [the two types are not interchangeable so different fixtures are involved]. I have tried T5 HO, two tubes over my 115g, and after a week it went back and I put two T8 tubes over it. Perfectly adequate as the photos illustrate. Here again, the least amount of light to grow the plants is preferable from the standpoint of plant growth, fish health and algae.
Hope that gets things started; don't hesitate to ask more. And thank you for the compliment.