I just do a sort of chicken wing input, basically a HCB motion starting with UF.
You don't hold up forward, you just start your input with it. You can get IA axe kicks easily this way, and It is the same thing as your input, only lacking the first DB input. (This is so much easier to explain with numpad orientation.)
You know you can do this with Gouken's tatsu as well, and Adon's jaguar kick, albeit, Adon's is only marginally more effective this way.
Ive been playing viper for very long time and she has so many ways to land her ultra.
makotos kara kara on the right i cant do it like 90% of time. On the left im very gd i land it like 90% in matches. Ex oroshi Walk over x up kara kara, has range so big ppl be mind blowned lol.
Here some other things i do
The basic ex oroshi neutral jump move wiff to kara beats everything besides reversal jump or back dash. To get ppl to respect your neutral jump kara i 1st do neutral jump heavy axe kick beats DP,jump and backdash. It gets blown up by some reversals like ex head but so u need to use her back dash safe jump mk.
Back throw shk wiff dash kara its a meaty so it has properties like abels tornado throw. back throw dash clk wiff to medium oroshi meaty link to ultra or wat ever.
LV3 FA--->LV 2 FA-->fwd lk to medium kara, its a meaty so they have to mash or jump.(Dont use on characters with gd reversals)
LV3 FA--->LV 2 FA-->fwd lk to shk to shp its a meaty so will combo or tag them if they try to run.