I've used the Dutch Biner in this fashion for about a month now with zero fears. The inside of the Biner is rather slim so it channels both of the amsteel lines longways vs a wider area that would allow for more sideways pull. I've also attached the biner using a larkshead which transfers the pull/force outside of the Biner... This is handy for attaching whoopies, but sort of recreates the problem of extra steps in attaching the spindrift.
I'm still using it... But in the end I found an $85 solution. A 2nd RR - netless.