My solution with the speed brake and parking brake evolved to be a bit more complex than what I anticipated to begin with.

The spoilers part is made from plate #9 + #10. They are glued together and then painted. Plate #11 goes on the side to cover.

The handle it selv is not the prettiest of things. Made from MDF. I tried to bent some metal but it ended up breaking the metal in two. So back to my old trustworthy friend MDF.

Again it is connected to a slide 10K potentiometer. Noting fancy here.

As with the throttle I use the furniture-fabric-do-not-scratch-the-floor-material from IKEA.

A servo is connected to the handle so it can push the handle / deploy the spoiler once the aircraft hits the ground. This is done via piece of plexiglas where the handle can move freely during flight. But once landed the handle will be pushed. See the movie to understand how. It was a bit tight to fit but I just managed. One disadvantage here is that I not am able to auto lower the spoiler. That must be done manually, even though it is a function on the real 737.

On the other side I fitted the parking brake. This ended up far more complex than appreciated.

I saw a video on youtube (That I am unable to find again) where the parking brake handle was connect to a wheel with two dents in it and then a wheel that applies pressure. This gives you a feeling of the handle locking when in the correct position.

Further more I have also installed a servo that works the same way as the auto deploy spoiler. When the parking brake is engaged you can disengage it by posing the two pedals. So when the toe pedals are posted the servo will move and pull the parking brake handle down. Pretty simple.