Training with dumbells at home

I work out at home. I have 16 inch dumbells, the problem is that I can only fit 6 5kg plates, 3 on each side giving me a total of 30kg on each dumbell. I need to use heavier weight on some excercises such as dumbell rows or pressing movements. I find it awkward using anything bigger than a 5kg plate on a dumbell, as it becomes harder to balance and even to lift up, got something to do with the centre of gravity I guess. Those of you who train at home, what you do? use larger plates on the dumbells or should I invest in longer dumbells? I can’t find any dumbells longer than 16 inches?