The CCTV solution is nice technological fix but why not avoid the inevitable issue of your box gutter failing and redesign the roof? Without having the plans, elevations and levels I would suggest that falling the roof away from the viewer in your image would allow you to collect the roof water on the (western??) side. There are ways to hide a gutter without hiding it inside your building and I personally think that one or two elegantly detailed downpipes can add to the quality of a building, why hide the obvious need to get water off a roof? Also, I would be very surprised if your architect doesn't already have a solution to this, it is a basic requirement of design.

Something like silver birch trees don't take up too much room but will provide some height and interest. Personally I pick out natives, after asking local garden centres for those which are natural to my area. I've used black mondo grass across the front of my walls with purple fountain grass behind it. The fountain grass really takes the summer heat, doesn't need much water and self-seeds. It's grown slightly taller than me after a few years. I have, what I call a 'survival of the fittest' garden. Over the years, I've experimented with all sorts of plants. Eventually, only those that survive with little help, and almost no extraneous watering, get to stay. One of the key things I did when planting out my garden was to dig down into the soil and lay a mat of used, natural-blend carpet underlay (not the more synthetic types used these days). Just ask someone getting rid of their old carpet- it's easy to come across. Above the carpet underlay I added water crystals, then put the soil back on top. After the gardens have been established, I haven't need to get the hose out since. I do have lots of succulents around the place, some native plants and ornamental grasses. I hope this helps.

We're doing the same, 2 sets. Want wood but have been told they "may" warp, even though under a covered alfresco. Don't have a firm cost yet but indication from builder is $10-15k more than powder coated aluminium. Total width of each set is 3250 divided into 3 doors, with stacking security screens. Don't have a price for the aluminium ones yet to compare but +$10-15k has probably helped with the decision. Have bifolds at current house but will be going for stackers at the reno house because they can have the stacking security screens, whereas bifolds are difficult to security screen, you can flyscreen but it's quite a flimsy arrangement.

We went with Monument and I am delighted. I was worried about it making the house hotter, but not at all as we added some extra insulation while the roof was lifted. We look over our roof to Mt Dandenong and it really feels like we are floating above the rooftops now (previously had a lighter color). I have also noticed there is far less glare being darker. Pic below is not my best shots ... but you get the idea. Forgot to add we also have a flat cliplock roof and used a combination of Monument and Dune on the house.