Gutter their must be on a 5 inch gutter system with 2x3 spouts. every 30 feet a downspout diverters must be at all valleys and porches. If you kew this great if not it has been proven and well some homes it does not look so good but it still is they way its needing to be done.
I see alot of homes today just passing by and well messes everywhere. Guys dont understand using tapcon screws to mount the gutter strap and i prefer a small 2 inch piece screwed in and met in the left or right side so you dont see the scres looking right at the front. Now i use 3 screws into the down spout at all points. you can also use the premade ones the same way but you have to meet at the front and make it tight. not all loose like i seen on my fathers house and tried to explain to a 62 year old man how to do it right. long story why i did not do it.
I have in the past like 5 to 7 years ago made custom flashing to stop birds and whatever else in the home at the soffit meeting the roof with a 2 inch gap. What i do is use that expandable foam to trap and kill the problem in the attic and build a custom piece of flashing to cover the 2 sides normal needed and staple them to the fascia board or nail it depends on height and pitch. Now i have to make 4 sided ones that never met at all. I do it with a 12 inch hand break.
hope this can some guys.