These gas blocks will be the clamp on style.
The SLR Sentry 7 .750 Adjustable Gas Block uses set screws.
Yes, it should be compatible.
This gas block will fit some heavy barrels. You will need to check the specific barrel to ensure proper size.
Yes it should fit
Yes. The one hole will line up the block with the gas port and keep the block from rotating or sliding. Both dimples would be better. Pinning better still. One dimple should work just fine. Most people never have trouble with no dimples. A high temperature locking compound like Rocksett will help to keep vibration from backing the screws out. SLR also sells dimpiling jigs that work with hand drills if you are so inclined. You can also use a steel blackening compound to protect the bare steel from corrosion if you don't have a stainless barrel.