One of my previous companies I flew for have over 30 years experience in the Antarctic operating Hughes 500, Bell 206, AS 350 and S76. Two of the senior pilots had over 2000 hours in the Antarctic and plenty of line pilots with over 5 trips which can be 3 months to 6 months. I think that makes them reasonably experienced. Most did not have an instrument rating ( class 1 in OZ) but did some practise IF training up to night vfr standard ( class 4 in OZ ), so that they had a good working knowledge of what the AH was all about and also NDB and GPS homing.
The idea was they would know how to home to their destination, remembering that a magnetic compass was useless due to the massive variation so close to the magnetic pole. GPS was not available in my time and map reading was not too easy, so NDB homing was important. Also by having sufficient skill to use an AH, they could cope with limited IMC flight to get out of whiteout conditions by doing a 180, they were trained to avoid it in the first place.
Finally 2 helicopters generally went together with half loads so that if one went down, the other could pick them up. Also the crew always consisted of some experienced Antarctic pilots to help the new ones. For example I went down with a pilot on his 7th tour on my first and even though I was the chief pilot, he was the senior pilot for that tour because he had the experience and I didn't even though I had 12000 hours compared to his 6000.
I do not recall any cfit incidents in 30 years, so I wonder if we planned our trips better than these 2 adventurers who of course are perfectly entitled to attempt the trip.