Shabat: carrying in a public domain

Carrying in a public domain on Shabat is one of the 39 kinds of forbidden work.

Tosphot and Rashi say to be a public domain there must be 600,000 people walking through it. 
The Rif and Rambam do not require any amount of people. But the road does need to be 16 cubits wide. Thus to the Rif and Rambam no Eruv is valid. So is one stuck? I suggest one can depend on Rashi and Tosphot in a case of need along with not setting down the package in the public domain but just carrying through it and setting it down in private domain. Thus there are two reasons to be lenient. But I find  Rashi difficult because in no Gemaras is this 600,000 mentioned and the cities in Persia (where the Gemara is talking about carrying) did not have 600,000.

רש''י and תוספות that say one needs ששים רבוא people walking through the central road to make it a public domain. The reason for doubts about this is the רמב''ם and רי''ף that consider a public domain to be just what it sounds like as long as the road is wide enough.

But the thing that makes this the most curious is that fact that in all the גמרות in שבת and עירובין that deal with carrying in a public domain there never seems to be the slightest consideration of this ששים רבוא. And the Jewish cities in Persia did not have ששים רבוא. 

{That however leaves the question of pockets- that does not seem to be the same as carrying in one's hands. The object is not nullified to the garment, but neither is it the same as carrying in one hands. To carry in one's pockets I think would be forbidden because of a separate law -the lifting and setting of one's body is like the lifting and setting of the object and as Rava says in Shabat page 8 that means even carrying on one' head would be liable. 

So pockets are out but carrying in a way that you do not set anything down in the public domain along with Rashi and Tosphot could be a decent permission.

שבת: נושאת רשות הרבים. רש''י  ותוספות אומרים שצריכים ששים רבוא אנשים הולכים דרך כביש מרכזי כדי להפוך אותה לרשות הציבור. הסיבה לספק לגבי זה היא שהרמב''ם והרי''ף  שוקלים רשות הציבור להיות בדיוק מה שזו נשמע אלא שהכביש הוא צריך  להיות רחב מספיק. אבל הדבר שעושה את זה ביעתי ביותר הוא העובדה כי בכל הגמרות בשבת ועירובין  עם שנושאות בעניין רשות הרבים מעולם לא נראה  שיקול של ששים רבוא,  ובערים היהודיות בפרס לא היו ששים רבוא

I would like to think about pockets more but at this point the issue seems to be in doubt. 

I have lots of areas where I am lenient but I do not write about them because the issues are not 100% clear to me. So I hesitate to tell others though I am lenient for myself. The general things I am lenient about are תקנות דרבנן in which the reason for the decree is bull as per the Raavad and Tosphot and Gemara in Beitza 5 and Gittin end of ch 1

So if you are looking for lenient decisions the general way to do this is to look at the question is the law derabanan and if the reason for it is null. The other common thing I do is simply look for a lenient decision in the rishonim, geonim or in the Beit Yoseph or Rema. 

I am not saying one should look to be lenient in law. However at a certain point I began to see that people could be extra strict in Halacha and still be scum. The extra strictness maybe even hurt.