Is there any relevence to the use of FM-immune equipment in class G airspace? the question put was simply asking if it was a good idea to descend below MSA in Class G whilst IMC. The answer is no! Not even if you think you know where you are. the MSA is there for a reason.
IO540, as you say, landing is a necessary occurance! it is not particularly relevent to the question, but a logical point to introduce nontheless. Each landing procedure has some kind of minimum imposed, even if it is a DIY, and each time, it is there for a reason. descending below it when IMC is asking for trouble.