If u want to knock this beast of an animal fast and efficiently u will need the following.

Upgrade station

Longneck rifle damage: 400 or more

About 200-300 narcotics

Arkomatic meat spoiler

Arkomatic terrateriam(grows crops more so put narcoberry seed in here need about 2-3 of these bad boys).

Discovery wyvern from the discovery mod(or just a regular wyvern with good health and stamina)

About 100 tranq darts

A backup wyvern(for if the other one dies)

Awesome spyglass

Extra narcotics(if giga is above level 125

And last but not least common sense

Hope this helps:)

Good luck