Hard to say as every bike can react differently. Yours have 2 x 160 MJ (cyl. #1 & #4) and 2 x 158 MJ (cyl #2 & #3). Going one step would mean you need to buy 2 x 162 MJ (for cyl. #1 & #4) while you install your actual 160 MJ in carbs #2 & #3. This could be a starting point but you need to fine tune your ride.
Also, stock needles will possibly be too lean and even beyond what shimming them could provide.
If you get a jet kit, better to use Factory Pro's as they use the same MJ sizes than OEM Keihin and they do not require to drill the carb's slides.