https://www.youtube.com/watch?v=atibnBS_MMQ

Excellent - I wish the previous owner of my van had seen this!
 
The big question for the OP is - AW11 or SW20?

Sdub of course!

Boo!

I splice my wire connections by opening up the strands on both and putting them halfway together. Then twist in the opposing direction on each followed by solder. My mother was an electrical engineer who put the electrics into Spitfire planes and showed me most of my electrical skills.

IMO I think soldering should be the absolute last option. 

Why?

There are obviously many looms with soldered connections which never have any issues. A crimp will hold up to environment and vibration much better whereas a solder has the propensity to fracture at the point where the wire meets the joint. 
 
How many professional motorsport looms have soldered joints. Very few unless absolutely necessary. 

I hear you, and I agree that solder does not provide a strong joint. 
You need both - a mechanically strong joint, and also solder to reduce the chance of corrosion, water ingress and vibration damage.
I disagree that crimping alone is enough.
I have seen quite a few connectors that have been crimped by others fail. 
I have never seen a crimped or twisted joint that has also been soldered fail.
You'll see that in the last joint that I demonstrated in the video, that I could pull on it pretty hard and it didn't come apart - even before I soldered it.
I've watched a few soldering videos on YouTube that are done by others, and very few of them do joints that are strong without the solder. 
I'm thinking of doing another video that actually stress tests (by adding weight) each type of joint, and will prove that my method is the best (I hope! :-) )

my 2c
1.All electrical boards are soldered not crimped.
2.Solder stops ingress from bad connections.
3.Solder doesn’t allow the same movement or flex but I’ve never seen a broken soldered joint.
4.A crimped joint will add to the resistance of a wire where solder will at a much lower rate. 5.All crimped connectors are used for ease of manufacture not because they make a better connection.
6.All aviation connections etc use solder (from what I know).