Tax Refund at Barajas Airport Madrid

Please I have a flight out of Madrid at 6.50am and I understand that the tax refund counters in T 1 & 4 don't open until 7am. I however understand that there is a 24 hour counter at T4s but my flight out if Madrid is from T2. I will appreciate if anyone can help with andwers to the following: 1. Is the tax refund counter at T4s open 24 hours. 2. Is there easy transport between T2 and T4s. 3. If the tax refund counter in T4s is in the boarding area, will I be able to access it as I will not be travelling from that terminal. 4. How much time should I give as my flight leaves Madrid at 6.50am. Looking forward to some help on this. Thanks