If you always punch when your weight is on your back foot, your reach will be limited. IMO, you should shift your body weight freely when you need.but the body weight is not driven over the front foot."
If we compare the stances that your punch can reach:
1. empty stance - 0% weight on leading leg.
2. 3-7 stance - 30% weight on leading leg.
3. 4-6 stance - 40% weight on leading leg.
4. horse stance - 50% weight on leading leg.
5. bow-arrow stance - 70% weight on leading leg.
6. monkey stance - 90% weight on leading leg.
7. golden rooster stance - 100% weight on leading leg.
empty stance < 3-7 stance < 4-6 stance < horse stance < bow-arrow stance < monkey stance < golden rooster stance