chilled/refrigeration (or other) shipping option question: how best to offer

Using ZC 1.5.6c, PHP 7.3.10, MariaDB 10.3.18, various plugins but for shipping particularly the standard built-in ones, plus 3 Japanese ones (old Nittsu module changed to Yupack, and old Sagawa and Yamato modules, all updated with October 2019 price schedules) which return a cost based on size and weight.

My question is about how best to add, for any shipping module, an option for refrigeration, for example, or oversize shipping for that matter. The figure charged in general depends also on size and weight.

One way I thought is to have a separate module up-front. This would be the most straight forward for calculation and offering of the option. But it makes it difficult to separate out charges in the final invoice.

Another way would be to have separate module offering a checkbox on products also selectable at final part of checkout (like the giftwrap module). This makes it easy to separate out charges in the final invoice, but makes it hard to calculate the correct charge, since the module would need to find out what shipping was chosen, and also have built-in all the different charge calculations for all the possible shipping modules installed.

Another way would be for each shipping module to offer an option, but I don't have any example to draw from that I could find in forum or module searches. This would make it easy to both calculate the charge, and separate it out in the invoice. But it would require changes to the display of the module in the offered shipping types (checkbox for options), or perhaps a separate screen at a later stage for options.

Any suggestions most welcome.

PS. I intend to upload the 3 Japanese modules (or rather, their classes) to the Japanese language pack thread later in the week.