Making a custom modular cable for PSU

[Azaloomi]

I have Seasonic X650 power supply and I need longer modular PSU to CPU 8pin cable than the provided 60cm (2ft). I tested the original cable and the results are in the image below. Do you need to connect the ground pins exactly as they are or can you make straight parallel connections, which would result in a neater sleeved cable?

I was told that pins 5 through 8 could be wired with a single wire, joint at the connectors. Is that untrue or just unadvisable to avoid overload? Are any of the other pins combinable to a single conductor? I will be using high quality silver coated AWG16 copper conductor, which should be able to withstand a good 20 amps or even more and the new cable length will be 140cm (4.6feet). I sent these questions directly to Seasonic, but you never can say if there's any replies to be had to these types of enquiries and if there is it's fairly common they are in a disclaimer form "don't do it".

 

[Azaloomi]

Surprise, surprise! Got short response from Seasonic technical team saying "chart you provided for revise is workable" - that is a reference to the same picture seen here. So I suppose the question about connecting every wire straight from one connector pin to parallel pin should be sorted. But I'd also be intrigued to know if any two or more wires could be run as a single wire? That would translate to less money spent on the cable and perhaps more importantly thinner overall cable running about my system.