Nervous bl3/bl4 blend won’t be light enough. Thoughts?

Nervous about my shade choice for 4 front veneers. My temporary veneers are b1. Defiantly too yellowish. While picking final color Choice initially decided blend of bl2-bl3. Doctor is very good and asked me to meet the lab technician who told me based on my current tooth color to go with bl3 with a slight bl4. Now mind you I want to go lighter than my natural shade. When I saw bl4 next to b1, I didn’t see a big difference. Can I see pictures of bl3 on a person? Also I’m fair skin. 50 y old