...... and by the way ........... I hated the Goblin Mini and it leaked like a bastard!
I had the earlier Aqua and liked it, but both this and the Goblin Mini are old tanks from a few years back, you'd be much better off buying a more recent one IMHO, like the ones on your original list, to learn on. Things have moved on and improvements have been made. When you've sussed a few builds, then you can go on to try random ones that catch your eye if you fancy it (I've done it for fun) .......... but they're usually cheap because they're old stock.
........ and if it helps, I build all my MTL tanks with 28AWG kanthal on a 2.5mm Inner diameter, 7/8 wraps making around 1.3/1.4 ohms.
@Hamish McTaxi if you fancy a real cheapo and don't mind waiting for delivery from China - you might try this. Cheap, simple to build, mine have never leaked. There are quite a few fans on here.
https://www.fasttech.com/p/6353800
I'm a great ape, not a dawg !
........ I know. You have to wonder if something got lost in translation!