A 200mm x 200 mm is plenty big enough for a bullet feeder.
The brass feeders are a bit of a different beast. Usually they are sectioned out and bolted together. Good thing if you ask me since my 3000x300mm CoreXY won't fit the case feeder or do so reliably.
Sectioned prints not necessary for the TylerR base. Look again at the last video above that I posted.....223 CASE feeder. My printer is a Creality CR10 V2, with a 300x300x400mm plate, but it can be printed just fine on the 200x200 if you do away with the skirt.....Many have done it.
The Ammo Mike design is suitable for most bullet feeders, but The TylerR improved design is big enough for 30-06 cases. Here's a video of mine......(again can be printed on 200X200.)
Not 30-06 because I don't shoot those, but this is .308.....
STL print files are organized and available free....even with a user manual, from the dropbox link at the bottom of TylerR's many posts on the Thread I linked to early in my posts above. So you don't even need cad software or ability, until you want to print your own designs. That's where I have an advantage as I've used Autocad for 30 years. But there are good 3d cad choices that are free, but there is a learning curve for any of them. Most of you guys have the advantage of youth....at 71 I don't learn new cad programs without a lot of hair pulling and anguish.....but it shouldn't be a deterrent to most of you.
TinkerCad is good only as a simple cad, training wheels. Fusion is good and can be free for home use. OpenScad super for software coders, and really stands out if you need to be able to apply endless variables. Ammo Mike & TylerR used that for plated design that can be endlessly variable. DesignSpark Mechanic is good, especially for those who don't have to unlearn traditional cad, like me.
There are several good slicers....most use Cura, I prefer IdeaMaker, but I was born a divergent.
BTW, Tyler has a new even bigger plate designed for those with 350X350 beds......same diameter as Dillon's case feeder.