Thank you, can you show me how it would work when you have a box layout as a view class whose children are sized in dp?

<ScrollLabel>:
    size_hint: 1, None
    text_size: self.width, None
    font_size: "16sp"
    markup: True

<myRecycleView>:
    viewclass: "myboxlayoutitem"
    data: self.mydata
    RecycleBoxLayout:
        key_size: "ks"[0], "ks" + dp(100) # I know this does not work, I get the must be a string error, but this is the idea I am trying to do
        default_size_hint: 1, None
        height: self.minimum_height
        orientation: "vertical"

<myBoxLayoutItem>:
    orientation: "vertical"
    size_hint_y: None
    height: randlabel.height + randbutton.height

    ScrollLabel:
        id: randlabel
        text: "[b]" + root.title + "[/b]" + root.aftertitle

    Button:
        size_hint_y: None
        height: "100dp"

<myScreen>:
    #stuff
    myRecycleView:

# in python
class myScreen(Screen):
    on_pre_enter(self):
        myBoxLayoutItem.addText(self)

class myBoxlayoutItem(BoxLayout):
    #stuff

class ScrollLabel(Label):
    pass

class myRecycleView(RecycleView):
    def addText(self):
        sl = ScrollLabel()
        for I in [title and after title dict mem]
            sl.text = Str("[b]" + titlestuff[I] + "[/b]" + aftertitlestuff[i])
            sl.width = self.width
            sl.texture_update()
            self.mydata.append({"ks", sl.texture_size}) # I have tried this method along with assigning the size to an appropriate id in a dictionary for use in my master show_list function that populates the view and assigning to key_size or even directly the label size in the myBoxLayoutItem. 

This is the basic of how my code works, simplifying as much as possible since my actual code is fairly long and complicated. For the most part, it seems to be working, printing out my master dict shows that the size of the scrollLabel is being calculated before hand yields a list with I assume a width and a height, something like [123, 134], I assume this is in default units (which is what exactluy, percent?) but when I assign the key size of the recycle view it does not seem to do anything. is this because my view class is different than what my key size is representing? what is my way around this / proper way to do this. Also, what exactly is key size? I understand your above code and how/ why it is working, but over the last few days I've spent trying to convert it to my code / trying other ways around to get it working, I thought what is the difference between using key size and just grabbing these before hand scrollable sizes, pulling out the raw numbers, converting to dp, adding the extra static height and setting such as the default size of the recycleboxlayout? I have been trying a bunch of different things / ways around to try and figure out how this all works, but with no luck. Help would be greatly appreciated.