How independent do you want? I just carried a load on company pallets and client pallets, tied down with company straps, arranged by company personnel, weighed by company personnel, loaded by company personnel, overseen by the same loadmaster that rode on the aircraft, and reviewed and signed for by the crew.
Over the years I've flown many passengers who did not declare their weight, and have used baggage that was both weighed (but not weighed in location on the airplane), using standard weights and procedures. I've carried cargo the same way, including liquid cargo; pump it aboard, carry what's determined by standard weights per gallon. Sometimes it may be heavy sometimes not. Our personal requirement is that we must revisit our calculations only if the weight changes by 10,000 lbs or more. This is generally the result of additional fuel being added, rather than a weight calculation error. Additionally, the checklist and flow procedures call for independent verification by both captain and first officer, and a comparison between the two, and a triple confirmation on the loading by the captain, first officer, and flight engineer, as well as by the loadmaster who usually rides with the load, calculates the weight and balance, oversees the loading and unloading, and makes determinations regarding each device or pallet loaded.