There's very few games where you need two legitimate giants (we did well last year with none). The Saints are definitely not an opponent where height will be a concern. As you say they have Bruce, but their next tallest forwards are Membrey (188cm) and Parker (190cm). Our mediums will be fine to take them on. I actually think this is a better mix, though I'd have preferred Moore to be playing over Roughead.
I'm expecting that Quaynor comes in if Moore misses and will play on the debutante Young (178cm). If not, it won't be over height as Aish would be the other option.