Matthew, it's what you think will look good and what you will enjoy building. Don't build for others, build for yourself. The Sdkfz 251 is a good idea as it means you can have infantry as well as armour in your dio. Do you plan on having them preparing for the battle, advancing to contact or taking fire? All things to consider before you even pick up a kit. If you're doing a prep dio you could have the tank crew refuelling and rearming. Likewise you could have the infantry putting kit in the halftrack-ammo boxes etc, adjusting webbing and checking kit. You could also have contact between the panzer crew and infantry via conversation and officers consulting a map, talking amomgst themselves (DML do quite a useful Kursk set for that-6456). These are all just suggestions so don't take it as "do this". This is how I work my dios out as usually when I build one it's a reasonable size (hence I don't do them very often lol- I'm currently working on a Hungary one 4 foot by 2 foot). Advancing to contact and under fire you'll obviously need completely different figures for both. It all depends what you want to show and how you want to do it. Sometimes I look at dios and wince as there's no thought gone into them, just built and cobbled together. You need a clear picture mentally before you start. I have an idea as to what battle/period I would like to model then read up on it and study photos for inspiration. Then decide on how I want to portray it-admin,advance,contact. Only once I have made that decision do I start buying the kits. Choosing vehicles is the easy part. It's choosing the figures that you need, to show what you want them to do that's more complicated, especially if they need modifying into the right positions. Always have a picture in your head as to how you want it to turn out and work towards that. Always have contact between figures as any group of people will communicate with each other so a dio is just that but scaled down. I know this doesn't answer your question as to which vehicles would look better (that's a personal thing) but hopefully it'll point you in the right direction planningwise. I look forward to seeing this idea take shape