What are your thoughts on opening an order on EURUSD with a lot size of 0.5?

i think so, yes

i mean: it’s all opinion, and different people will always have different opinions! i don’t know if it will suit you, and i don’t know if it will fit well with how you trade, but what i do myself is to put the stop-loss a couple of pips beyond the last swing low or high (depending on whether it’s a long or short trade, of course), and then work out my position-size after seeing how far it is from the entry to the stop-loss, so that the percentage i’m risking always stays about the same

we were just discussing it in another thead - i said a bit more about it here and here, if it helps …

As long as your account size can hold. This question is very subjective to different people, accounts sizes , trading styles and possibly leverage.