I like to place Bora as stronger than Blue since Tao Pai Pai at least bothered using his hands to deal with Bora, whereas against Blue he noticed he hadn't to even use his hands, which is a more dignified way of dying than with Blue. Still, he seems considerably below Goku as, although barely, Goku could climb all the way up to Karin, while Bora mentioned iirc that not even in his youngest days he could accomplish the task. So placing Bora as right around Namu's power, maybe slightly higher works for me. Having said that, it could go either way, though I think Bora could maybe edge out Namu with his spear.