What to do if it is already 7:00 or 8:00 pm?
At that point, your strategy needs to change. You are no longer planning a trip; you are organising an evening.
First, stop comparing too many options. Open the flamenco in Seville page and check which tablaos still allow bookings for your date and party size. If an option appeals to you and the time is realistic, secure it.
Second, calculate your arrival realistically. Many venues recommend arriving 15 to 20 minutes early. Do not book a performance you could only reach by running from the other side of the centre.
Third, check what the ticket includes. If you have not eaten yet, an option with tapas or dinner can solve two needs at once. If you have already eaten, prioritising the show alone will probably make more sense and you will not pay for services you will not use.
Fourth, do not assume you will be able to buy at the door. Online booking with immediate confirmation is much safer when only a few hours remain. During the Biennial, extra visitor demand may be concentrated precisely on last-minute performances.