If your existing ones are ET+05 then an ET0 (zero offset) wheel will stick 'out' slightly further. It works the opposite way to what you think; positive offset means the wheel sits in towards the drum / axle and negative offset means it sticks 'out' further. So if you're talking clearance to the side frame of the trailer then an ET0 will be better than ET+05.
https://www.performancealloys.com/alloy-wheels-offset
https://www.performancealloys.com/alloy-wheels-offset