Which sigurd

I would go for the +def one. That hits 37 defense which is pretty incredible, and although -spd gets him double more, he has a lot of protection against doubles. -atk is probably usable since 32 isn't bad, and +spd hits a solid 35 if you want him doubling others more often.

I’d go +Def/-Spd. +Def feeds Bonfire and his ability to eat double attacks is strong. Buffing speed [and attack] with multiple Goad Cavalry can compensate -Spd to ridiculous heights, so you might not even notice the -Spd in Horse Emblem.