Rambo hood sizing

Hello, I am new to the world of Rambo blankets and just purchased my first one this week (whoop whoop)! I ordered the new Rambo original turnout with leg arches heavy weight in a size 72". My horse has been a 74-76" since forever but I ordered a size down per recommendation from Rambo representatives. My question is - what size hood should I purchase? According to the size chart I would need a size medium but given his traditional rug size being about a 75", should I order the large? What is everyone’s experience with the hoods? Big, small, or true to size? My horse is a 15.3 TB gelding with a normal neck (not short not long). He does have a nice top line and is fairly muscular. I am at a stand still with which size to order. Some knowledgeable advice would be greatly appreciated! TIA

My 15.3 lightweight warmblood and 14hh stocky Irish cob are both in large hoods.

Thank you this is very helpful!

Their catalog breakdown was S-69" M-72"-75" L-78"-81" XL-84"-87". When I worked at a tack store, we had more exchanged for being too big than being too small. A large was plenty big on my 16.2h TB that wore a 78".