So, looking at both Talents, consider any given 2-minute window.
SW generates 1 HoPo every time you use HW. With 0 haste, that would be 1 HoPo every 15 seconds, so 8 HoPo in 2 minutes. (Assuming you can use it off CD without delaying CS and J - i.e. this is an overestimate)
HA generates 2 extra HoPo every time you use CS/J or a GC proc during the 18 seconds of HA (12 globals with 0 haste). Mapping this out means you should:
CS - J - X - CS - X - J - CS - X - X - CS - J - X
Which is 7 x 2 = 14 HoPo assuming no GC procs. (X is any filler, doesn't matter which for this example).
So you have 14 HoPo compared to 8 HoPo which is an extra 2 SotR. Therefore with HA you get at least 2 extra SotR's per 2 minutes. (5% extra uptime).
To combat this without doing several calculation, to get 14 HoPo from SW every 2 minutes (to make it equal to HA with 0 haste) you need a Cooldown of 120/14 = 8.6 seconds. This would amount to 75% Haste.
I think I can stop at this point, because HA also scales with haste, so would improve AND 75% haste is practically unobtainable and that amount of haste would affect the rotation with SW anyway and would probably push HW back at certain times. Meaning that for DTPS, because HA generates more HoPo than SW, it should always be ahead depending on how much damage reduction you get from approx 5% extra uptime on SotR.