Should you go all in castle against Byz as Franks and should you open up with knights or crossbows?

I feel like Byz can defend all in knights a bit easier than crossbows because they have two cheap counter units against knights as opposed to one. If Frank player goes crossbows and seige than Byz player will probably need to have crossbows, skirms, and seige and everything except for the skirms are generic and not discounted. But Byz always have the potential of fast imp so if I don't quickly do enough damage all in castle I'm in trouble. What do you think?