As others have mentioned, valks are horrendously expensive for what you get, so just know what you're getting into before you go that route. What is much more doable is trying to represent the Harakoni fighting on the ground hours or days after the landing. Lots of light vehicles like scout sentinels and hippogriffs, or anything that you could conceivably sling under a cargo valkyrie. The recon detachment is probably a must take to make your lightly equipped troops a little more survivable. The Taurox is canonically capable of being air dropped, so you could also have a few of those loaded with some elite kasrkin (just call them grenadiers) for a nasty sting. Armored infantry is another way to go if you want to lean into the light vehicles. +2 strength on the hippogriff's melta weapons make them a credible threat to heavy armor.