I know there are numerous threads on this but I want to build up a cross check with flat bars. That will effect sizing right?

I'm 6 feet tall with inseam about 33.5 with shoes off.

I'm in between a 56 and 58 and cant find lbs with stock to try out. I'm leaning to the 58 because the short head tube and becauae I'm using flat bars.

I ride a 56 supersix evo and keep reading on these forums I should either stay with same size or size down. The 58 CC top tube would be 2cm longer compared to my current bike. I don't think the standover height should be an issue with shoes.

When I look at hybrid bikes with flat bars I notice the top tube is longer. This leads me to believe the 58 might be good for me?

Thanks for any imput. I plan to ride this bike in bad weather and around town. Use it like a commuter or take it out in bad weather when I don't want to take out the other bikes