Loft board orientation for best loading
The load will be transferred to the supports mostly based on how you stack it, not how the sheets are laid.
OSB has a dedicated (and labeled) strength axis. It's normally lengthwise with the sheet. While your OSB may be thick enough that it doesn't much matter, it's almost never appropriate to run it parallel to the joists. If you don't have a compelling reason to do otherwise, install it perpendicular with the joists.
Also, stagger the sheets. You should not stack joints like you have. Instead, start the second row with a half-length sheet and lap past the first butt joint with a full sheet. This allows the tongue-and-groove connection between sheets to help support the area around the joint. Even if you're not using t&amp;g doing so will help stiffen the floor.