In the previous flush trimming pictures, you might notice that my right handed saw was pushing the cut to upwards or to the right.. this is fine, except my next cuts were "behind me". And I had that damn post to deal with, the notch for which you can see in the last pic. So I gave up and moved back across the deck and started there. Now my cuts and my saw guides were moving in the same direction.
Here you can see several boards that are very long. These were ten footers, chosen because between these posts the deck frame was extended and that meant the deck got extended too, so, longer deck boards. Now I had to cut these off flush too. This needs to be a precise cut, so I have to know where the underlying frame member is, and measure from there.
I used the blade of a combination square to reach through the gaps in the boards and slide it back until it made contact with the frame. Then I made a little pencil mark. I did this on a few gaps and used them to define the line for the saw guide board I'd screwed into the deck.
