deck floor board decision

Neither. I'd have increase the spacing just a tad so the last board was either a perfect fit or damned close to it. Or closed them up to add another board.

If the boards are typical deck boards with a rounded edge you don't want to rip it unless you can round the edge again. If you can't do that, put the ripped edge to the outside.

Why to the outside? Is there an advantage to that? Surely not looks?

I would do it based on looks. It will show up a lot less on the outside than making that one gap look different than all the rest.

What deck boards are you using? If you are using 2X6 PT, why not just get a 2X8 or 2X10 to cover the last 2 pieces.

The deck boards are 1X5 5/8 with rounded edges.

Surely it IS looks. Look at he space between the boards. Note the rounded edges. Now rip a board and put it in it's place. See how ugly it looks by comparison. If the ripped edge is on the outside, it will not be next to another board for the visual difference. . Yes, it is all about looks. if you have a router and can put the round over back on, it will make no difference.

I built a deck with EON (plastic deck boards). A tip in the instructions said that if you can't fit the last deck board then just 'sister' onto the last joist board to extend the deck so that the last deck board fits without ripping. In your case maybe another 2x + 1/2 inch of something else to give you 2 more inches. Kevin

I ended up putting two full boards and have 1.5 inches overhang. It ended up okay. Thanks fellas.

That works. If it is in an area where people can walk, put some support under it. If it is under the railing, it should be OK just as is.