CB250 Wheel help

[JamesFace]

Hey guys, I'm new to the forum and to the custom bike building.
I've got myself a CB250 k4(i believe) and I'm converting it to a cafe.
I don't much like the stock wheels and brakes. so i was looking to get some new wheels.
i can't seem to find the same size wheels however
              Stock                            New
Front      18"x3.0" drum              17"x3.5" disc
rear        18"x3.5" drum              17"4.25" disc

that's about as close as i could find. 
I was just after some help as to whether they will fit, or where to get some ones that would (i live in aus)

thanks guys

[Big Rich]

Putting 17" wheels front and rear with disc brakes is a pretty large undertaking. A front end swap along with a swingarm swap is necessary. Why not just get a cb360 front end (disc brake) and lace up wider rims? That will open up plenty of modern tire sizes.......