Hah, DLV is it's own track for sure... not another like it I've ever been on
It's definitely not the most pursuiter friendly track!
My theory on arm positions... yes they matter some (aerodynamically) but the real sweet spot is finding the arm position that allows your head to fall into that -almost- turtling position naturally (not forcing it though as that's tiring) Whether that's mantis'ing, Tony Martin "scooping" with narrow pads, wide pads, whatever gets your head nice and tucked.
(Reason being... I've never seen anyone's aero data where "turtling" didn't make them faster... and it's usually a/the most significant gain.. so sacrificing something else to make that natural is usually going to be worth it.)
I think in things like a Kilo though, there's the extra stability you'd get from wider pads, which would have to be helpful at full gas.