The 200 size is too small; as in way too small. I can elaborate if you want me to, but it comes down to effective IPT and cadence.
A 400 size would be great (for my preferences), a 300 size would do it too (for me). If you like the 300 size better, go for it.
The Cardiff is the best bang for the buck, as has been mentioned. Even if price was not a matter of concern, I'll take the Cardiff over the Luna. I've owned and fished both. The Luna is a solid reel of course, but I prefer Shimano's VBS casting.
Haven't ever fished a Conquest, but I did own a Calcutta 401TE. The Calcutta seemed to cast lighter baits (~2 oz) better than a comparable Cardiif 401. Maybe because it's narrower (not sure). With heavier baits, there was no difference. The Calcutta of course is way more refined than a Cardiff. All Cardiffs I've fished have/ had a peculiar geary feeling on the retrieve which might take a little getting used to. The Calcutta (or Conquest) is worth the extra money over the Cardiff. I'd rather buy a few baits with the money saved though, but that's just me.
EDIT: With the Cardiff's, you have to unscrew the three screws on the handle side to access the brakes. Not so with the Luna, or the Calcutta 401TE (not sure about smaller Calcutta TE's, D's or Conquests).