Level of dragon and order they are placed in the Breeding Cave makes no difference what so ever. I ran a comprehensive series of breeding tests with Air and Mud dragons in order to make Sandstorm, and the results are at
Does dragon order and/or level impact probability when breeding? but pasted below.
Player Level 15
Air 10 + Mud 4 - 50 attempts
- 21 Fog
- 27 Mud
- 2 Sandstorm (29th & 47th)
Player Level 15
Mud 4 + Air 10 - 50 attempts
- 25 Fog
- 21 Mud
- 4 Sandstorm (6th, 22nd, 31st & 32nd)
Player Level 15
Air 4 + Mud 4 - 50 attempts
- 21 Fog
- 24 Mud
- 5 Sandstorm (5th, 11th, 38th, 43rd & 44th)
Player Level 15 - Hit Level 16 after attempt 34
Mud 4 + Air 4 - 50 attempts
- 24 Fog
- 25 Mud
- 1 Sandstorm (15th)
Player Level 16
Air 4 + Mud 10
- 21 Fog
- 26 Mud
- 3 Sandstorm (18th, 43rd & 44th)
Player Level 16
Mud 10 + Air 4
- 23 Fog
- 23 Mud
- 4 Sandstorm (20th, 21st, 31st & 48th)
After 300 attempts in the Normal Breeding Cave.
~6% Sandstorm on average
~6% Sandstorm with Mud on the left
~7% Sandstorm with Mud on the right
~6% Sandstorm with a lower level Mud Dragon
~6% Sandstorm with a lower level Air Dragon
~6% Sandstorm with 2 Level 4 Dragons
Player Level 1
Air 10 + Mud 10 - EBI
- 25 Fog
- 19 Mud
- 6 Sandstorm (4th, 5th, 6th, 10th, 37th, 40th)
Player Level 16
Mud 10 + Air 10 - EBI
- 23 Fog
- 23 Mud
- 4 Sandstorm (7th, 9th, 19th & 20th)
Player Level 16
Air 10 + Mud 4 - EBI
- 17 Fog
- 28 Mud
- 5 Sandstorm (14th, 20th, 24th, 40th, 48th)
Player Level 16
Mud 4 + Air 10 - EBI
- 22 Fog
- 23 Mud
- 5 Sandstorm (10th, 11th, 15th, 35th & 43rd)
After 200 attempts up to ~10% chance in the Epic Breeding Island.