Thanks for the advice about Angel Wings. Was debating wether it was worth giving it a try but hesitant due to the cost. If I can multiply using cuttings it becomes more palatable.
Also I'll bare the advice about pre soaking the gel in mind, I hadn't thought of that.
WRT colours the plants I listed are what the local garden centre had that they though could work in the pots. It covers a few shades of green, silver and some muted yellow/red. I would really like some vibrant red and even yellow foliage, but as I want to avoid seasonal plants if possible they didnt have any options for that.
Due to the size of the pots, adequate water and drainage were two issues i'd been advised to consider by the garden centre. I may well have gone overboard on the drainage plan. Irrigation should hopeful remove watering as an issue.
The internal design of the pots is to