When then they're slings you don't have to watch body language lol.
The slings can jump quickly just like a juvenile can. If a .5" sling moving quickly freaks you out then a 3" T moving quickly will make you crap your pants. Especially if its your first T and you're still iffy about them. I guess it's just a personal view on them then. A .5" sling taking off on me is like "ohhh get back here you little cutie! You're so silly!" A 3" T getting away from me is like "oh blank, where the blank are you going? Holy blank, chill the blank out psycho!"
Three inches on a ruler doesn't look big but a 3" spider is huge compared to any spiders you've ever found in your cold, clammy basement, Anna. :D