Air carrier Captain reported three non-compliant loading and DG placement issues discovered during preflight which were later corrected.

Narrative

Upon inspection of DG (Dangerous Goods); FO informed me of a non-compliant pallet. Issues identified were 3 in number.1- DG package upside down relative to orientation arrows2- Aisleways not clear 18 in (45.72 cm) from pallet edge3- Opaque plastic used and restricts inspection of DG pallet IAW (In Accordance With) FOM XX.XXFO informed DG agent that pallet was not acceptable. Agent asked my FO to ask if I could accept the DG instead. FO notified me and showed me the pallet. FO is 100% correct and I informed the DG agent that indeed the pallet was unacceptable just like my FO told him. DG agent asked me if I was removing the position from the flight. I told him it was noncompliant and said he could tell me what he was going to do with it. DG manager came out. Wanted to argue that we were going to be late. I told him the pallet was non compliant and showed him why. They reoriented the upside down package without correcting any other items and asked me to approve it. I said no because they still had a problem with the aisle ways and inspect ability due to opaque plastic. Additional load team was brought on board and they pushed and shoved to get the packages clear of the aisleways on the left and front. Multiple times they asked me if it was ok but the aisleways looked too narrow. I asked them to produce a tape measure and measure it. One of them produced a conversion from inches which seemed false but would make the data fit". 18 inches is 45.72 centimeters. In the process; a non DG package was crushed on the bottom and the DG on the other side of the pallet (AC right side) was extending beyond the edge of the pallet. I asked if the overhang was acceptable and he said yes. He asked me if the pallet was ok then. They had still not removed the opaque plastic. I pointed it out and said no. He told me they were going to download the pallet at this point and I returned to the flight deck. After a few minutes the agent returned and asked for us to look again. They had removed the opaque plastic and rebuilt the pallet to be compliant. I could not see the crushed non-DG package. I inspected the pallet and found that it was now in compliance.Initial inspection items not in compliance or unable to be accomplished. Cause: Incorrect DG pallet construction. Either lack of knowledge or willful disregard. Apathy on the part of managers to provide correct supplies. (clear plastic sheet) A DG manager told me his supervisor said it was ok to use opaque plastic instead because the pilots were accepting it. Ramp managers need to provide their DG crews the tools to do the job. Sticky notes affixed to the outside of opaque plastic does not fill any requirement and in fact encourages non-compliance. It does not relieve the need for clear plastic. Captains are at fault for signing for non-compliant shipments. First officers are at fault for not identifying problems with DG positions. Both are at fault for accepting the status quo.DG load crews need to know the procedures and adhere to them. Aircrew need to follow the procedures in the FOM and have the willingness to hold the standards. Ramp managers need to provide their DG crews the tools to do the job. Potential for loss of hull or life."