I think I already answered, but SI isn't 100% necessary until deeper. I die if I don't have it at DL60, but you would likely die without it at DL45. At DL35 you should be OK using a swap for SI when you get a message about "it" doing something.

Hi there,

I left you a comment in my own character dump, then I realised that you really don't have to check my dump

Thank you very much for your tips, this is the first time I go down so deep in Angband. As for what I've been reading about the competition, it's important to have SI and FA... I'm getting it from the weapon... So... is it better to wield another weapon that deals more damage instead of having SI and FA? Or should I switch weapons when in melee?