I agree about 100% with what UpdateLee posted , above.
Not sure about the shielding, nor coverage, but double or quad is probably a waste for most of us.
The Snap 'N Seal or equal compression connectors need a special tool to apply, and I've seen 'em at Harbor Freight, though I haven't tried theirs and cannot recommend it.
The one I used was all metal and had a ratchet so you couldn't do a half assed job.
Once you began, you had to compress it all the way before the tool would release.
I think it was in the $60 to $75 range, and if I needed my own, I'd look real hard to get one for half that.
The proper stripper to match the connector is a necessity, too.
I used a $10 one, but it was really not the right model.
I think you need a 2-blade, not a 3-blade, to prep the cable properly for the connector.
Since I don't recall, maybe others will chime in or you can at least be on the lookout for a proper tool.
The only other thing, is to color-code your cables some way.
There are many, but pick one, and make sure each cable can be identified uniquely at both ends (maybe in the middle if that's important to you).
Oh, and as for the connectors, look to pay around 30¢ or so.
Under 50¢ is good, and I don't think you can find 'em down at 20¢, but it's been a while since I shopped.
Just don't want to see you paying $1 each!