This problem only looks complex, it’s not easy either. I’m working on similiar solution now.
WooCommerce doesn’t support hierarchical attributes. You can’t define quantity attribute as parent of volume (m3) and weight (XX tons) options. I wouldn’t separate them – logically this is one attribute (and size is second). Drawback: there will be a lot of variants (5 * 28) – you have to define prices for all of them!
On front we have two select fields in standard theme.
Modyfying size parameter is simple – replace select with radio buttons (with jQuery).
Quantity parameter select can be replaced with more elements – radio buttons for volume options and select for rest (weights). Choosing any of these options should update form value of original (now hidden) quantity select.
After this we have two attributes (both have to be choosen): size (granularity) and ‘kind of quantity’. I wrote ‘kind of quantity’ because beside attribute selects we have original quantity input. This way we can order f.e. 2 bags (quantity input) x “0,7 m3 minibags, 8-16mm” (variant of 2 attributes).
It can be sufficient (standard) solution for many cases … but this way we have an option to order only one kind of quantity at one time. This is good for cart, adding the same variants we’re getting one line with updated quantity.
Looking at image you need something more usable – ‘quantity multiplier’ for each ‘kind of quantity’ (checkboxes for volumes + select for weights). It can be achiewed with more JS on frontend (array of quaintities for choosen quantity kinds) and filters on backend (woocommerce_add_cart_item_data, woocommerce_before_calculate_totals …). It could have drawbacks, too! – f.e. one cart item of set (1×0,5m3 + 2×0,7m3 + 12ton) – adjusting quantity in cart we’re changing amount of sets, not individual quantities.
Using filters we have possibility to almost freely adjust all prices and delivering costs. This way we don’t have to define all variant’s prices – we can calculate them from needed volume and/or weight! In practice this is only one price (per 1000kg) for each of granularity variants – volume prices can be calculated from weight. Bulk quantities select (25 options) can be replaced with single numerical input (minimum 10[t]) and unit price corelated with ordered quantity (cheaper for greater orders). The same (parametrized) calculations can be done for delivering costs (kind and quantity of trucks, distance).
As optimal (usability, UX) I would create complex frontend (product page) allowing mixed amounts of ‘kinds of quantities’ but added to cart as separated items (lines) for better manipulations (quantity adjustments) and readability.