Mike I agree with the others completely that 2 ballscrews is much much better and prefered. . .BUT . . . I do know from experience with pritty much the same size machine it will handle wood, even hard woods no problem. Yes you won't be able to be has aggressive as if you had twin screws regards DOC etc but it will do the job ok. It will cut Ali but very light duty with shallow cuts.
You will need to widen the distance between bearings, more the better, and make the gantry as stiff as possible. The gantry width on the pics I've shown is 220mm with 240mm of actual bearing spread because it use's profiled rails not round and the bearings are slightly longer than the mounting pads so effectively 240mm wide gantry.

If you can stretch to twin screws then it's a no brainer just do it.!. . . but if not then I recommend you design the end plates for twin screw upgrade in future. The machine I showed in the pics is done this way.
The pics don't show it.!. . . but because I use Timing belts to keep the motors on the inside, the end plates are drilled at either side on the inside to accept twin screw setup and can be upgraded at any time.
It's a simple case of removing the existing single screw remounting the BK/BF blocks on the inside of the outer profiles and mounting the motor bracket setup in it's new locations on the end plate. Obviuosly then you add the extra screw along with a extra motor brackets etc. It also means a new ballnut mount for both sides so the existing one is not re-used but that's no big deal or great expense. All in all it takes 2 to 3 hours to change from single to twin screws.

In your case with direct mount motors just have the end plate machined at either side to accept the motors then cover with blanking plates untill ready, then just swap when ready and cover single screw mount with one of the blanking plates.!! . . .Simplizzzzz.