Answer 1.
Generally the gear gives you the best amount of drag. On my aircraft type (A320) though you cannot drop the gear until below 25,000' and less than 250kts. There are no such limitations for the speedbrakes. The gear makes a lot of noise in the cabin, especially at high speeds
Answer 2.
Most aircraft have some warning indication of flying with power against speedbrake. Have been in just this situation. We descended early, slowed down and flew level with Flap 2 for about 20 miles. Deployed gear slightly early. Worked very well.
T'Bug
