I have relatively large hands, and find that the Bessa trigger winder on my R3A provides even more hand holding stability, especially with the Grip A, which doesn't interfere with the trigger winder throw. Unfortunately, both the Grip A and trigger winder are now discontinued, but still in stock at some dealers.
I've had a similar results with good sharpness at 1/4 second exposures. I could count threads in my son's T-shirt with the 21mm f:4 handheld at 1/4 second, and they showed no blurring.
Lee