I like Alliant 20/28 for both my 28 and 20 gauge loads, and Winchester 296 or Hodgdon H110 (they are the same powder) for the .410 bore. Keep them both in Winchester AAHS hulls!
Listen to "icy" and Shamus. I've also used Unique for 20 and 28ga loads when 20/28 powder was unavailable.
28 Gauge load is HS-6 and for the 410 296. I try to come as close to factory in both the AA HS and STS hulls. Both powders work great for me. May be a little dirty for some of you, but I like the way they pattern and break birds. I have found that some powders don't pattern as good as these do. So for me I will stick to HS-6 and 296. By the way HS-6 is the same powders as the discontinued Winchester 540, if you didn't already know that.
Longshot Powder is the Go To for 20 ga. 20/28 is actually a Magnum Powder just look at the pressures of the factory burn rates. the .410 is rifle powder. HS-6 is Mag Powder, why not look at the Mfgrs. Specs like I do and be Famialiar. GB...……………………………….DLS