Advice on Pole gutter Gutter / roof leaking

[Kenneth Hynes]

I am in the middle of a BRRR on a 1900 era house in PA. It is a two unit , with the upper floor being a separate apartment that is part of the renovation. I am trying to run down / fix a leak that is happening on my second floor bedrooms. There is no plumbing near the leak so believe it is coming from the rail / gutter system in between the 2nd and 3rd floor floor. had several roofers and gutter guys come look at it and all offered different opinions. I have had one work on some of the gutter system but it doesn't appear to be helping.

thinking of DIY with some Leak Stopper  Rubber flex tape .  Anyone used this ?   Appears the problem in around the area where the gutter is curved going around the concave turret looking windows 

interior leak  2nd flloor ceiling

outside view of 2nf/ 3rd floor gutter system 

some previous treatment 

some treatment

close up 

another view

right now looking for any ideas.  contractors around here are little bik flaky about scheduling   and rates are $100 plus so doent want to make another mistake in hiring the wrong treatment