You can speed up the blasting by dividing the contact number into several tagging and blasting campaigns.
For example, you have 1000 contact numbers. You can divide into 4 different CSV files which one file will contain 250 contact numbers.
By using these 4 CSV files, upload them into 4 different tagging.
After creating the tagging and uploading the data into the tagging, you can create 4 different blasting campaigns. Meaning that, you have to repeat the steps for WhatsApp Blasting, 4 times.
At the end, you will have 4 different campaigns that run in the same time which,
1 minute = 4 messages.
HOWEVER, YOU NEED TO BE AWARE OF THIS METHOD MAY GET YOU BEING BANNED BY WHATSAPP IS VERY HIGH.