Heres You and idea to reduce the sway.
Go to a local d-net dealer or Dow electronics's (E* distributor) and size up you some E* adjustable Struts that come with their Super Dish.
One lag per foot and Either you can drill your mast and insert one bolt all the way through to 'catch" both adjustable strut arm supports. And if they extend long enough you can actually attach them to the bottom side of "chunk' of the dish itself.
Ive got a pic here somewhere of one i did like this because cx insisted on a roof mt and no ground pl mt. Its on the orig At-9 though if i remember correctly. the roof pitch and simple physics in support with that mono pole support junk just would cure too much But a visual appearance of support.. So realistic physics and weight/wind brought me to these support arms & that thing wont Move period.
Only prob i see you may have is the over all length issue of the struts fully extended, But Regardless if they reach the top of that mast i guarantee if placed in the right symmetrical positions on the mast you will eliminate the "sway".
Ill edit this post if i find you a picture w/ those support arms.. btw that install looks nice.. Drip loops and all.. Good Job.
EDIT. (pic)
100% roofing bull covers the whole "foot" and support arm penetrations not this D* issue bishops tape and silicone mess.
I laugh at those guys who use silicone for a asphalt based shingle or rf compounds. The 2 compounds dont fit together period.. (lol)
Theres you Another thing forum to go check... your roofs after those D* hsp's have left.. LOL