Not being funny but I think to attempt to use a guttervac on 4 storey buildings is just plan daft as they are not all what they are cracked up to be. Reasons being get one with loads of sods in especially in corners and you are screwed especially if the gap between the roof and guttering is narrow. Some goes for badly blocked downspouts also you run the risk if you damage any plastic joints/brackets again you are screwed as you have no way to get up there to fix it.
For cleaners that use a guttervac will know it's hard enough sometimes using a guttervac clearing guttering & unblocking downspouts on 2/3 storey jobs let alone 4 storey.
That’s why I say 4 storey guttervac work sucks
