Congratulations on completing your law enforcement career, and thanks for your service.
Other people can help you with the scope question better than I, but are you sure you want a NULA in .300 Win Mag? It would seem like a dream retirement rifle would be one you would want to enjoy shooting a lot. I have a NULA in .257 WBY, and its recoil feels more like a 7mm does in a standard weight rifle. I think a .300 Win NULA would be snappy.
Clearly recoil tolerance is personal. I had a "perfect elk rifle" built in .300 Win: McMillan, trued Rem 700, Shilen, Jewell, etc. and ended up parting it out because the .300 was just more recoil than I shot well.
Today's good bullets also mean that lots of smaller cartridges are perfectly elk capable out to 600 yards.
My apologies for causing you to doubt a decision you have already made, but it would be a shame to have a 30 year dream rifle not be something that brought you as much well-earned joy in reality as you had imagined it would.
