In gliders I use my wife's hair clip: to retract the gear, first take
the clip off the gear handle and put it on the spoiler handle.
Then raise gear. When pulling spoilers for landing, if the clip is
in the way, put the gear down and put it on the gear handle, then use
spoilers.

Not perfect (what if I'm getting sucked into a cloud?) but it's worked
so far...

In my club's B4, we used a short length of a heavy duty cardboard roll
the same way. One day, a bunch of years ago, the Kinsman ridge was
cooking and the clouds were just above ridge top and I had to run the
ridge at 100 knots and/or spoilers to keep out of the clouds. I kept the
gear up due to the high speeds. I got used to using the spoilers with
the cardboard tube still on it. You know what happened but because the
landing was on grass, only the paint was slightly scuffed (a B4 is
metal, BTW).

The fault was clearly my failure to use a proper landing checklist. I'm
MUCH better at using a landing check list now :-). Still, when I bought
the LS6, the first thing I did was to install a gear warning.

Tony V.