Magpie,
Sorry been a crazy weekend and I missed your reply to me here... I didn't mean to confuse you further. My point was that you are so back and forth on what to do and how to care for them both, that is why I reiterated that it had been suggested to try both separately...
No one is saying you can't do it or it hasn't been done and done well... The issues arises in the pure fact that discus are new to you and you are now trying to learn them and take care of them in a tough environment... If I had never played baseball or swung a bat before, would you think it would be in my best interest to start by having a major league pitcher throw me 99MPH fast balls? You see what I am saying? Everyone's concern is that you are ripping the swimmies off and dicing in the deep end without really knowing how to swim... Grasping the concept and researching is one thing and great... Once those fish are tanked and you start to care for them and problems arises and such is when disaster can set in...
If you are adamant about doing this, which it seems you are, just be aware of the pitfalls and be ready to put the time and effort needed to get things going. It sounds like you are ready to buy adults, do water changes and put in the proper care...
It also sounds like you are ready to tear it down should things go south... Do you have another tank that you could pull plants and move them if need be...?
A drip system is nice but not a replacement for water changes... Most only do a small % which isn't enough and the debris and leftover food and poop is still present which is really what corrodes the water, not removing just the water. So even if you had a 100% daily drip, without siphoning and cleaning the substrate, it isn't really doing much. Now if you can combine the two then you may be in business... until then, do your big water changes and good siphoning... make sure you can get in and around the plants as that seems to be the main issue with keeping planted tanks, debris gets all in and around the plants and just sits and rots and hurts the water...
Some use dedicated feeding areas in the tank so the food trys to stay condensed to one area, but even that is tricky...