Great Thanks, seems a good start and I will try it and get back!

Since you are using the manufacturing module, try out the module: MO and BoM variance whose author is intelliVersal integrated solutions. This module generates a variance analysis report showing the quantity and cost differences between BoM and actual MO.

You can achieve it using module Automation Rules​and Odoo Studio

1. First create a new field using Odoo Studio in product form for checkboxwood​product (ex: labelis_wood​)
2. Create new automation rule that trigger when the product variant​inside BoM form is changed.
3. Add this sample code 

# search wood product
wood = env['product.product'].search([
    ('x_studio_is_wood', '=', True)
], limit=1)

# automatic add wood as component
wood_bom_line = records.bom_line_ids.filtered(lambda r: r.product_id.x_studio_is_wood)
if not wood_bom_line and records:
    wood_bom_line = env['mrp.bom.line'].create(dict(
        bom_id                  = wood.id,
        product_qty             = 0,
    ))
    record.update(dict(bom_line_ids=[(6, 0, wood_bom_line.ids)]))

# put your custom formula here based on weight, height etc
product_variant = records.product_id
quantity = product_variant.weight + 7777

# update qty
wood_bom_line.update(dict(product_qty = quantity))