I'm glad I'm not the only one interested in my thread :lol:
The first point I'd like to make is that the key to a successful planted tank is balance. This can be achieved by matching high lighting with pressurised CO2 and an extensive liquid fertiliser regime. Or it can be achieved by carefully selecting your equipment to match your budget. If CO2 is not an option, less lighting is used or the lights you have are mounted further away from the aquarium. A low tech tank that has balance can be just as beautiful as a high tech tank, although it will take a little longer to develop.
Lighting. If I were you, I'd use that T8 double unit only on this aquarium. Get some new tubes (perhaps power glos or just 6500k cool daylight tubes if you're on a budget) and mount that directly on top of the aquarium. 5cm each side won't be noticeable and with your tank 40cm deep, it should give you a nice amount of light without being too strong and causing algae. I'd be running the lights for 6hrs initially and seeing how that goes. I'll base the rest of my answers based on that lighting set up.
CO2. With that sort of lighting, it's unlikely you will need CO2 to keep algae in check but it wouldn't hurt to increase plant growth. But seeing as your tank is 160L, a cheap sodastream setup is out of the question and rigs take a bit of cash to set up. Leave it at no CO2 for now.
Fertiliser. Now you've mentioned substrate fertilisers but not liquid ferts. I feel that neither are really needed in low tech tanks but they do help to keep algae at bay (provided you do the right water changes) and increase plant growth. I've have some of my best success with inert substrate so I'd be sticking to that unless you have heavy root feeders such as swords.
Filter. Now this is an interesting one when aquascaping. Aquascaping as a game of aesthetics and having a great big filter pipe through the middle of your scape is really unattractive. Think about this when getting your tank made, I suggest you allow for the pipes to come through the left side of the aquarium so they can be hidden by the natural reflection of the glass. If you were really keen on aesthetics, lily pipes are another option too but again must be mounted on the side, not the back of the aquarium. The issue you may have is lack of flow within the tank, algae is a real issue in any spots that don't get enough water movement so extra pumps may be needed, you won't know until you start the tank though.
I find the Aquascaping World Forums to be the most useful in terms of aquascaping aesthetics, their plant knowledge is good too. May I suggest you have a look through these: 2010, 2011, 2012, to get an idea of what sort of tank you might be after.
Hope this helps!