XC Spikes for Ultras?

Has anyone used spikes to run part uf an ultra?
I have just entered a 100mile run in jan and am probably going to encounter ice. My normal shoes XT Wings won,t be much good but could be used with Katoola Microspikes. Has anyone tried to seriously run with these. The other option is to use XC Spike shoes as the weight will be similar. I will be probably carrying a 8Kg pack (Full MM kit + extra winter gear + food). The pace has to be slow so carrying and swapping shoes will not be a big deal.
Having run the first 50m of the L100 in fell shoes (Addidas swoops) I know how the lack of a shock absorbing sole can bruise your feet. Do all XC Spikes have minimal cushioning?

Maybe yaktrax could be an answer here. Ice grips that go over your shoes. Running in spikes is no good idea in my opinion but then I can't even manage 4 mile race in them, they hurt my feet.

The majority of competitors in the Baikal Ice Marathon seem to use yaktrax. 

This is probably relevant. 

XC spikes have no cushioning to speak of, they are made for grass. Not mud, rock, or any hard surfaces. XC's average 10k distance, so completely unsuitable for ultras.

Mark777

Spikes are awful on anything hardpack, I think it's a dreadful idea. I've trained on ice in mine, but I'm guessing you'll be out for more than 40 minutes.

you've got to be kidding