Installing a System Cado wall unit with 3 sections in a new house. Picture 1 shows two of the sections in a previous house. Picture 2 shows the wall where the 3 sections will be hung contiguously. The attached .pdf plan shows the rail locations (2 per section) relative to the wall studs.

There are 4 predrilled holes per rail. The wall unit rails will be mounted with 2.5” wood screws where there is a stud behind the rail location, and toggle bolts (3/8” or ¼”) with a flat head 3” screw where there is no stud behind a rail. Screw and toggle bolt size is defined by the diameter of the predrilled holes in the rails.

Referencing the .pdf plan, rail 6 on the far right (see Detail C) can be screwed into the stud through ¼” blue board with a 1/16” plaster skim coat on it. However, both rails 2 and 3 butted up against each other will be mounted using toggle bolts (see Detail A).

The plan assumes the studs are exactly where shown in the .pdf. Not able to guarantee this, worst case is that the 2 rails for any one of the sections must be attached using 8 toggle bolts (4 per rail). But will 8 toggle bolts be sufficient to support the weight of 1 cabinet and 3 shelves?

A google search found a document on shear and tension forces referenced in a few other forum threads that discussed System Cado. See https://www.factsfacts.com/MyHomeRepair/drywallfastenerstrengths.htm

The attached spreadsheet shows my calculations for each of these forces for 1 cabinet and 3 shelves all empty. Shear force is not an issue. The initial calculation of tension force (without supports for the shelves) showed a load problem. But the supports are needed to hang the shelves (see Picture 3). This dramatically reduces the support load where is appears tension force is also not an issue.

The key question is: Is my analysis of the shear and tension forces correct?

Related questions are:

1. The shear and tension force calculations do not take into account the width of the cabinet or shelves (all are 31.5”). Does this width matter when calculating these forces?

2. Each cabinet is hung on the rails by 3 beechwood doweling pins that are exactly adjusted to the 45° diagonally bored holes in the rails (see Picture 4). Likewise, shelf supports have 3 dowel pins for 12” shelves, and 4 for 15” shelves (see Picture 3). Do these dowel pins help mitigate the tension force on the rails?

3. The cabinet will be hung beneath the shelves (see Picture 1). Does this placement help mitigate the tension force on the rails?

My thanks in advance for any feedback.