The round Robarts hinges are very easy to install as all you need to do is drill a hole to suit the hinge. Just be sure the pivots are aligned before the glue sets.

I thought I'd like demountable control surfaces so I'm using heavy duty Dubro hinges with cotter pins.

Making the slots is a pain, but what I found helps is to drill a series of small holes with the drill press at the proposed hinge location (into the edge) ... makes it easier to dig out the wood.