Carlita's mainmast is very easy to raise single handed, except for spinning on the handle nut to lock the heel in place.
The trick is to prevent the mast from rotating aft with my right hand reaching as high as I can with my right arm while trying to spin the handle nut on the forward facing bolt at the bottom of the mast that is out of sight with my left hand at full stretch.
I have never failed or had an accident so far. Sometimes it takes a few attempts and it seems to be getting harder. One of my concerns with this multi tasking is that while I am concentrating on trying to keep the nut in plane, perpendicular to the thread axis to get the thread to start, with it's long one sided angled handle arm, I not keeping up the force with my right hand. What if I start to relax my right arm while I am engrossed with the bolt and the mast is heading south before I am aware?
Our good friend the late Peter McRary was concerned about it on his CS17 mk3. He rigged a temporary forestay just for mast raising. It worked but I don't want any more jobs or clutter to add to my rigging and unrigging.
My demands were: It had to be automatic, no clutter, out of the way and reliable. Easy to unlock when unrigging. I chose a force of about 10 pounds at shoulder height to unlock. My first design started with a piece of sail batten for a spring and a wedge. It would have worked well on mast raising but It would have required reaching down under the mast to release and start to lower while bending down. I could have run a line and cleat to release from on deck but I ruled it as clutter.
Here is what I came up with. The temporary lock is located below the mast. It has a spring loaded plunger (red) that is pushed down by a 3/4" wide plastic striker(white) running fore and aft in the mast heel that has an indent to hold the mast in place while I spin on the handle nut. The dark brown block is a spacer to position the plunger in the right place. The green part is the channel that the plunger travels up and down in. The dark blue part is a threaded cap that screws in under the spring that allows for assembly. There are 2 2"#10 pan head screws holding it all in place.
The cut away view is scaled twice normal size for clarity. The picture was a quick and dirty test model to prove that it would work and test the release force.
All I have to do now is to hold Alan down long enough to feed it into the 3d printer.