It is neither risky nor difficult. Chop throttle, slow down, then alt-x and drop flaps. In a B-29, that will bring you from 30k down to 3k in about 5 minutes. No lost drones, no watching the speed gauge required.
Ok, I was happy to have tried this in the TA last night. I took off from a 30k base, established my alt at 32k.
1) Chopped throttle until 200 mph.
2) Began dropping flaps (I dropped full flaps).
3) Made sure I was flaying manually and not auto (personal choice)
4) At 150 mph, executed ALT-F4 errrrrrrrr ALT-X
5) Decend rate was at -4k plus.
Here is the interesting thing. With full flaps down and alt-x executed and plane decending (B-29), you can actually power up to 100% throttle and establish a decend rate at -2k. If you want time to go afk for several minutes adn have a long way to base still, you can keep your speed up and still decend. I had my throttle at 80% and went down at -3.0k per minute.