Flare jets are the most commonly used jet style in various NOS applications.
Funnel jets are typically used in four and six cylinder Sportsman Fogger kits, motorcycle, watercraft, and snowmobile kits.
The funnel jets are used with poly line and flare jets are used on race kits with braided steel lines.
If you have a serious kit, use flare jets. Don't get brass ones, they are inaccurate and erode away. Get Stainless jets. NOS reckon they test every jet they produce for accuracy.