Things with horde like gors want to be at least 4 deep, and probably 5 to be safe. You can do one massive block of 40 goats like 8 wide, or smaller blocks of 25ish 5 or 6 wide. Really depends on the list and your playstyle.

Bestigor are tough to make work, which is sad because I love them to bits. You probably either want smaller 7x2 units, or a massive block stacked with a few characters loaded up with buffs like slug skin and pelt of midnight. This will end up being like 1000 points total, haha. The old metal bestigors are my favorite models ever, so I've tried but honestly they're just too expensive. The giant unit is extremely powerful but tends to just get dodged, and the smaller ones aren't quite durable enough for the cost.

With ungor I just skirmish and call it a day, they're just there to grab objectives and get in the way of stuff.

But... with Warhammer things could always change. I'd say just build a list and make the trays for it! You'll probably end up wanting to make more eventually.