I think your basic spec is quite correct. Naturally more is better, but my PC and laptop are about the same.
My laptop is a Dell 6420 with a ram upgrade to 8GB, bought used on ebay about 3 years ago. I believe the CPU is a mobile I5 equivalent. The NV graphics is a bit dated and has only 512MB ram ...

I'll be using this, thanks

The money I spend in virtual worlds is insignificant compared to everything else that's happening financially.
So, no different really. However time is getting eaten up just keeping track of events.

Quayside now has an Early Aeroplanes exhibit, period about 1910.
There's a teleport from the arrival point to the exhibit area.

There are several unscripted antique aircraft available for copy with full perms.
Each one contains a licence notecard and another with some brief details.
Some of these ...

Kitely changed to VAR regions several months ago, so anything regarding Mega Regions no longer applies.
There's some information here https://www.kitely.com/virtual-world-news/2015/12/04/big-kitely-worlds-will-soon-be-converted-to-varregions/#disqus_thread

in one of the comments it says
"are you ...

I don't feel the need

I knew that - but I still have to "like" it

Multiply by 256, so
3x3=768x768
4x4=1024x1024

In world those are metres, in a terrain file they are pixels.

The upper height limit is also a multiple of 256, I can't offhand remember if in Kitely it's 4096 or 8912, but it's probably so high you don't need to worry. You're unlikely to make any ...

I would start at the Virtual Outworlding Blog by Selby Evans
http://virtualoutworlding.blogspot.co.uk/2012/09/kit-content-creation-build-script.html

This has some pages with topics foe beginners like this
http://virtualoutworlding.blogspot.co.uk/2015/11/2015-new2-basic-building-in-virtual.html ...

A standard region is a 256m by 256m square.
This was originally the only region size available in OpenSim.
"4 regions" could refer to 4 separate regions, or it could be a block of 4, making a 512m by 512m square.
Now that we have variable size regions, you might see a 4 region world referred to as 4 ...