Pat has given you a lot of great info. I would add that old pressured boars should be considered as a different species than just average hogs.
I have chased them for over 40 years and this is what my experience tells me. Do not shoot monster boars with any conical broad head. A broad head that will pinch right through a 175 piggy will often fail terribly on an old shielded boar. A 2" thick shield will severely decrease penetration on many 3 and 4 blade heads. A 2 blade head will cut through a shield without any issues. Shoot a heavy arrow and get as close to 50 pounds on the bow if you can. Penetration is critical when you are shooting an animal that is 24"+ thick if you are going to cause multi system failure. This is important because the blood trail will likely be sparse at best and nonexistent from a tree stand.
Get a string tracker. Let me repeat that... Get a string tracker.
Hunting giant hogs (300 pounds plus) is a totally different game than "shooting pigs". Put pressure on him and he will be gone for weeks. A 5+ year old boar is the smartest animal on this planet. NOTHING gets me more fired up more than hunting a ghost boar.
If this boar has been night hunted before I would recommend a light system that is NOT bow mounted. Where legal, a stationary light controlled with a dimmer switch is the way to go. I have tried every color and I always come back to red on the big old boars.
Putting the sneak on a giant boar in most conditions that he will choose to bed may well be impossible. I can tell you that if you bust him out of his security area, he will likely be gone forever. I personally would find his preferred exit and or travel routes. Think of it this way... someone tries to rob you on the way to the store vs someone trying to rob you inside your home- which would have the most adverse impact on your future actions?
If you have not read this story, give it a read. There are some good lessons included that will help you understand what you are up against.
Good luck.
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