Sure try it. But my experience with such triplet lenses is wide open a bit too soft and a bit too little contrast. I'd still close down a stop or two. But experimentation could be fun of course.
the red windows on back are frame counting, obviously. YOu use the one nearest the end of the camera with thekey that winds the film for shooting. If you have/are using the insert for the camera that converts it to 4 by 6 (half frame, 16 shots per roll instead of 8) then you use the lower window first.
Some of us just cover up the unused window with back tape to avoid confusion.
I've learned so much about how to use this old camera lately that I made a video to document it. That is supposed to help me to remember after I use other cameras and come back to this one again.
uncocking without losing an image will not work at least in my Bessa I since there is a double-exposure-prevention-technique built in. Shooting only when film is transported. see arrow near shutter-release-button.
my Bessa I has Vaskar 105/4.5 Prontor -S with 1/250 quickest and X-synch only. SV has also M-synch. Sorry for omitting quoting someone above.
With the 400+ film I bought for gray days the sun has been shining brightly ever since and I didn't want to wait so it was tested at the absolute extreme of f22 & 1/400.
Going to that "absolute extreme" 1/400 f/22 would be required only for snow scenes.
Normal exposure for sunny weather and 400 speed film is 1/400 f/16 or any other equivalent combination.
With negative (color or bw) film, your image quality has more to lose from 1 stop under exposure than one stop over.
Even with the basic method of average metering, a sunny weather scene often meters at (for 400 speed film) 1/400 f/11 (or 1/200 f/16, or...), because: (a) some parts are open shadow; (b) trees, grass, etc, are darker than the "standard middle gray" (whatever that is, please do not open that can).