Linear Bearings Mounting Positions

Hello I am very new here and to the CNC world and I am wanting to build my own CNC. My current plan is to build a 1515 lead screw machine but instead of gantry plates and wheels I want to do a 3/8" aluminum gantry riser plate and use linear rails with that. My main question is, can you mount linear bearings (HGR20) sideways and is that positions stiff enough and will it wear out the bearings on one side too much? I'm wanting to mount them on the side of the C-beam and mount directly to the gantry riser to avoid needing to weld on or attach another plate with bolts to achieve a flat position of the linear bearings.

Thanks, Thomas