i would probably try for at least 90cm but depends on the size and shape of the room, location of doors and windows and size and shape of other fixtures..can you post a plan of the room?

2500 x 900 or the 1000. Aim for 1100 - 1200 between benches.

1.4 x 1.4 is pretty pokey , and no , I suspect an 820 door will be too wide unless you swing it outwards , which is just weird . If it swings inwards , even if it at 90 degrees to the toilet itself , there will be almost no room for a person , a WC and the door 'swing' . Most doors are at the end of the room , the WC at the other end , and that will make it even worse -- if the WC protrudes 50cm from the wall , and your door is 820 , you have 8cm in which to stand ! Setting the WC 'offcentre , the door off-centre the other way gives a bit more space , but add a basin and you have an obstacle course to negotiate . Is there any way you can take the length to around 1.8-2 metres ? A width of 1.2 works , 1.4 might sound better , but with only 1.4 of length you are pretty much stuffed . .

You have an ensuite and an identical bathroom around 3 steps further apart. Can't see any advantage for this. You could lose the ens, relocate the WIR and end up with a bigger bedroom, bigger WIR and save money. Your roof has these eaves all close together over what appears to be some upper level windows, but these walls aren't reflected below. If I've understood this correctly you've added significant build cost for little gain. I think the room sizes are ok but I would suggest a design professional to polish it up.