Hello, Laura.
Strictly speaking, no, two filters aren't really needed but because I'll be using very high levels of light more flow is needed to distribute nutrients/co2 and it helps to safe guard against possible dead spots. One filter with a 1200lph capacity would meet the 10x an hour base rate which would be sufficient if using lower levels of light because co2 demand will be much less. Flow could be increased by using additional pumps such as the koralias but I find them one of the ugliest thing you could put in a planted tank, up there with plastic divers or concrete castles. Another thing to consider is that glassware regarless of maker has the ability to destroy the flow rates a filter produces because the inlets are too small and too few, inline co2 diffusion like I'll be using and an inline heater add further stress which reduce flow.
Really it's a trade of thing, more light means more flow and faster growth but more balance issues, lower light means lower flow, slower growth but more stability, something that will be a massive boon early in the start up stages or as a beginner.
Regarding the glass wear I'm only going to be using one set initially choosing to use the JBL kit with a jet mouth which looks very good, this is something of an experiment as if it'd good I'll be replacing it with a custom made glass version from my unis science labs. You're right that it may make the tank look cluttered but I think for the choice of planting I'll be taking it shouldn't matter too much as it will be dense enough to hide the most part of them.
Unfortunately I was homeless over the summer and my last few scapes never reached maturity, firstly succumbing to damage during transit to leeds then once I had them reestablished and thriving falling victim to a family dispute which left me sans abode and having to tear them down and moth ball all the equipment till somewhere to live was found, not being particularly interested in photography because of my poor ability to take photos meant that photos are few and far between. My cube has been my best/favourite tank, my last 60cm my favourite scape but neither had a photo taken to show their final state. I'll search my threads and try and find some pictures.