I bent a gas welding rod with a handle for depressing the self adjuster and keep it with the brake spoon.
While you are in there replacing you shoes do a good inspection of the brake hardware. The reason I had to pull my rear drums when I got my truck was because one of the retainer springs broke and let the brake shoe grind away at the inside of the drum. Also the parts of the spring got between the drum and the friction pad.
The brakes still worked sort of and the truck was loud enough that I barely heard a faint screeching noise.
Anyhow I just replaced both rear drums, new cylinders and all new hardware.
I make it a habit to replace my hardware after several sets of shoes anyhow because I have too much invested in my truck and it is soo heavy to have it not stop because I wanted to be cheap for about $20.00.
I also only use the best shoes and pads I can get from my local supplier, not the lifetime ones from the local chain store.
To make them last a lifetime they are usually rock hard and they screech like a cat in your fan.
Also INSPECT and adjust them regularly and do not trust the self-adjusters,
The pedal feels great when they are adjusted right.

BTW don't forget to replace the keeper on the axle nut.
Jim