I have not tried the simple layering you mention; I assume you are trying to form roots at a cane node where the cane is pressed to the ground or slightly buried. I have done a fair amount of tip-rooting, and the canes will let you know when it is time because they will cease growing in length and if a tip meets an obstruction (brick, stone, board, etc.) and is touching damp soil, it will form whitish roots that look like a little claw. Occurs sometime in autumn. At that time the cane is most ready to root-propagate. It is high time now to tip prune for lateral formation. At the first sign of new protocane growth from the tip roots next spring, cut the old cane or lateral about a foot from the tip-root and transplant, keeping a good chunk of soil with the tip root assembly.

The lower laterals will be best suited for simple layering; I think you might have a hard time getting a main cane bent over for ground contact. The tips of unpruned canes will of course eventually curve back nearer to the ground.

Thank you for replying and providing the info I was seeking. As you confirmed the proper time for both tip layer and simple layering will occur in autumn. I'll start tip pruning all primocanes now.

Thank you for explaining the proper procedure. I appreciate your help very much!