His tips are good, but similar to the instructions that come with most detergents intended for down products.
One of his tips is to include tennis balls in the dryer. I wish I could remember where I read it, but somewhere I found instructions that said this was a common suggestion but shouldn’t be tried.
Instead, these instructions said, you should take your bag out of the dryer every few minutes and fluff it up, breaking up the clumps by hand. This way, you don’t run the risk of damaging the baffles and stitching.
I don’t know which is the best way, but a few weeks ago I washed my Marmot Arroyo 30-degree bag with Nikwax Down Wash and tried that drying technique without the tennis balls. I was impressed with the results.
When finally dry, my sleeping bag was as fluffy as a cloud.