I hope this isn't a klutz kasha...
The Gilyon HaShas cites a Teshuvos HaTashbetz which says that no matter how big or small the sukah, the shiur needs to be 1X5 width to height ratio. He also says (the part i'm focusing on) that a stam sukah is 4x4 amos which is why our mishna speaks of a sukah at the height of 20 amos.
If this assumption is true namely that a stam sukah is 4x4 amos in width I think the Tashbetz would have a difficult time with a case on 4b. The gemara there speaks of a person who puts four "kundisin" at the end of his roof. Now, if a stam sukah is 4x4 amos in width and the case of "kundisin" is where the rooftop is ten tfachim off of the ground, according the maan diamar that we say "gud asik"- mimah nafshach theres no nafka mina because this roof is chayiv in a maakeh! (and t/f one cannot lichatchila go there) And if you say there IS a maakeh- then what's the chidush of kundisin? I have four walls! (I am assuming that one cannot lichatchila place himself in a place which is chayiv in a maakeh and that the rooftop in "kundisin" in 10 tfachim high. I believe these are fair assumptions)
I hope I was clear and am looking foward to hear what the Kollel has to say!!!
The Chazon Ish (CM Likutim 18:2 v'Hinei) writes that there is nothing to prohibit someone from going to a roof which has not had a Ma'akeh installed.