advice on end-joining 150x38 handrail boards

Hi,

I'm after some advice on the best way to join a handrail board end-to-end to make it look (and function) like one continuous board.

I have a 5.6m span along one side of my deck, and am planning on putting in a handrail of 150 x 38 ironbark (matching timber to my decking boards). The handrail will be supported by intermediate 90x90 posts at 1100mm intervals. One intermediate post (at 2200) passes through the handrail, as does the end post at 5600. The other end butts against the brick wall of the house.

The local timber merchant has a piece of 150 x 38mm which is 5.4m long, just 200mm short. Murphy's law. Although I could put in a join around the post at 2200 (i.e. use a 2.2m and a 4.4m board) I'm wondering if I can add 200-300mm at the end of the board to make it the right length. I'm thinking of a biscuit joint, or a scarf joint, or a half lap joint, but my knowledge of different techniques runs out here. Any advice appreciated. It would be located near the house, right in the corner of the large deck, so wouldn't likely take any load or indeed even be used.

Also, I was thinking for where the two intermediate posts go through the handrail, I'd jigsaw a 'U' in the board and slot it around the post. Could I buy a japanese thin kerf handsaw and attempt to use the piece cut out of the 'U' to fill the 'U' once the handrail was in position? Or would the kerf be too large?

Thanks for any advice guys,

cheers
Tom