Greetings.
Nice little azalea there! So not sure the cultivar. Is this Yves Murasaki, or a Murasaki.
If the former, not familiar, if the latter this is a very nice satsuki azalea, with 1/4 Juko heritage. That matters as Juko types tend to be somewhat brittle.
You requested to know how to make this cutting into a whip. That’s very easy… just like you mentioned follow the main line and remove all the side branches leaving only the top cluster of leaves…. Then remove the buds. This will leave the azalea with no branches, no clusters, no buds.
Be sure to cut flush and seal all wounds with Top Jin (Amazon) cut paste.
View attachment 589670
I would wait a week or two to do this, but not longer.
Each time the cluster produces branchlets on top, choose two and remove the rest. After a week or so, choose the strongest and remove the other. Then grow this out… removing all side branchlets that form.
Using a heat mat thermostat combo and light can boost the growth during the winter.
Not sure would wire the whip at this time. There are embedded sharp bends that can be used to embed in the future design
As this cutting is likely 2-3 yoa one might consider bending the lower part of the ego. It already has a good angle coming out of the media,
Good luck! Please post future progress.
Cheers
DSD sends