decking stairs

[Terry7556]

i hope this is the right place for this, was,nt sure if i should have posted in stairs,
anyways just finished a small deck, 2.4mt x 1.2 mts for acess from the kitchen to the garden through a pair of doors.getting ready to do the stairs, my height from top of deck boards to the slabs below is 25 and 3/4 ins or 655mm to you youngsters. can you offer an opinion on the goings and risers i should use. its likely to be open toed and i thought the goings would be 2 deck widths, about 290mm or is that not reasonable for the height i have to work with?
any advice is welcome, thanks in advance

 

[r896neo]

that will work in quite closely with an off the shelf riser package if you want to make it easy on yourself. They tend to be 150mm/6'' risers. As for treads they are as you say usually 2 boards width