It seems the Starting area size option has no effect on Gleba starts, if there even is a starting area. Regardless of the settings, it seems to spawn enemy nests very close to spawn. At the same time, there's not really any starting yumako or jellynut, requiring either long belts (which, especially with the first tier, are terrible for latency), or scouting far from spawn for a suitable spot, which is likely to be surrounded by enemy nests.

I would rather not have to fight a stomper in order to be able to automate iron.

I mean, Gleba is probably the most difficult planet to start on, but... You're guaranteed to have both biomes adjacent to the starting area, Jellynut gives a speed boost to get to and fro, stromatolites give you a crap ton of iron/copper starting off, and fruit lasts quite a long time.

I haven't touched the starting area at all, which means that it not being affected by the sliders is a space age bug or a missing feature, and making enemies further out probably isn't a good thing anyway because you need pentapod eggs to progress.

Are you really fighting stompers to automate iron? They only spawn from regular sized egg rafts, not small ones, and only start appearing after 10% evolution. I heavily doubt anyone would be experiencing stompers before getting a couple biochambers and furnaces running.

I'm going to assume the "starting area" slider is a variable that only affects Nauvis, but I could be mistaken

The closest yumako and jellynut trees to my spawn were very far apart with plenty of cliffs and water between them and it, so I went scouting for a better spot. The best spot I found that was in close proximity to both had a regular sized egg raft not too far away and it really did have a stomper wandering around it.

Just adding my experience from a few hours of attempting a Gleba start with another mod meant to make it actually easier (On Wayward Seas)

There's rafts that spawn regardless of the starting area slider, but playing with the slider does change nest density ever so slightly.

And IDK if you tried clearing even a small egg raft with a pistol and the 10 rounds of yellow ammo but I ended up punching it, and without constantly munching yumako I would not have survived, especially after popping the raft. A few times I didn't, and that was just to get all the rafts sitting IN the starting biomes.

I tackled early Gleba just like I would tackle early Nauvis, with some differences. Early iron/copper comes from stromatolites. Early fuel from either wood or jellynut.

I found it pretty viable to research gun turrets and make enough turrets/ammo before killing an small egg raft or two to get the eggs for biochambers.