One hand or switch handing needed for straight shaving?

Yes, true...still a little tough to go lefty but it does work and a little clean up with a single foes wonders...lol.

i use right at times ..sometimes both i use a shavette does the trick

I use both hands. As a left-handed person I am generally ambidextrous because I live in a right-hand dominant world. If this is causing you some concern you can lather up and use a shavette without the blade in your non-dominant hand just to get the hang of it. It won't take you long to build the muscle memory. I have tried to use just my dominant hand for both sides of my face but it feels awkward with a SR.

I agree. I'm a righty, but reaching across with the Japanese-type grip was more awkward to me than learning the left handed standard grip. I'd recommend going the extra mile to learn with your weak hand.

When I first started, I decided to use both hands. It was interesting in the beginning but I found that using both hands also gives me different angles. For example, ATG on my left upper lip is easier with my right hand and vice versa.

I'm currently relying on only my dominant hand. I plan to start using my other hand as I become more comfortable with proper technique.

I use both hands.

This thread takes me back to when I first started to learn drums. Drummers refer to our non-dominant hand as "the stupid hand"
it's all about repetition and muscle memory. Takes a bit of commitment to learn a new skill, but the payoff is in the satisfaction when it finally clicks. For me, I'm on shave #50 with a Weck - it's getting easier every time. Looking forward to trying an actual S/R in the future.