I might detail my way of doing it a little further and it might help you as well.
I practically do as you do, I have a single construction TF where all ships gets assigned to when created.
I also have one "Reserve" TG for each Task-force where I then assign every resource that I want to belong to that particular Task-force. This TG is obviously created in such a way that it is part if that said Task-force. When I move a ship from my construction TG to the Reserve TG the ship will then automatically belong to that Task-force.
In the "Naval Organizational" tab I do not include this Reserve TG since it is quite dynamic. What I do is to create all the TG and subgroups of those TG. Some ships are more or less permanently assigned to certain TG others (like escorts) are assigned when needed using the "Naval Organizational" tab. I then create the TG from the "Naval Organizational" tab and I have my TG ready to sail off into space.
I also organize sub groups under each TG if it has escorts or scouting elements that often break of from the TG.
One example might be like this...
RD1 - 1st Independent Recon Division
RD1 - 2nd Cruiser Squadron
RD1 - 2nd Cruiser Squadron - #1 (element #1)
CA RSS Juggernaught
CA RSS Juggernaught - Hangar space
RD1 - 2nd Cruiser Squadron - Scout #11 (Element #1, detachment #1)
SC Scout01
RD1 - 2nd Cruiser Squadron - Scout #12 (Element #1, detachment #2)
SC Scout02
RD1 - 2nd Cruiser Squadron - INT #13 (Element #1, detachment #2)
INT Interceptor01
INT Interceptor02
INT Interceptor03
INT Interceptor04
INT Interceptor05
RD1 - 2nd Cruiser Squadron - #2
FF - Rodrigues
FF - Sebastian
FFL - Valasquez
RD1 - 3rd Recon Squadron
RD1 - 3rd Recon Squadron - #1
CL RSS Benedict
CL RSS Benedict - Hangar space
RD1 - 3rd Recon Squadron - Recon #11
SC - Scout03
RD1 - 3rd Recon Squadron - #2
CL RSS Rangoon
CL RSS Rangoon - Hangar space
RD1 - 3rd Recon Squadron - Recon #21
SC - Scout04
etc...
I don't have to place ships in the structure all the time, but the base structure don't really change all that much. Some element might even be empty at time even on missions, but they are there and can be filled quickly when needed.
The first letters in my naming standard are basically for ease of finding TG in the TG drop down list, this way they are always sorted in Task-force then Task-group then Task-group elements and last Task-group detachments.
It also give me a sense of military discipline when I play.