3 sigurds which one to use and what character can make use of spd smoke

I'd say +speed -def. 31 defense is still very high, and as for who can use speed smoke, I'm not sure.

Do you want an offensive one or a defensive one? I would say + defense if you want to use him as a player phase unit, and +speed - defense for an offensive set. If you want him for both you should pick either of the + speed ones. I have heard -attack isn't that horrible on him, so you could go with that if you want to preserve his great physical bulk, but like Sci-Yan said he has good enough defense that you could take it as a bane and not suffer too much.

Mine is +SPD -DEF and I have no complaints. Not sure that I'd want a different set of IVs if I had the option.