Odd you should ask... I am just finishing a complete reinstall of TS12 as I type.
The order of install I used successfully is as follows.
46957_to_47059 - 1 - Hotfix 1.exe
47059_to_48249 - 2 - Patch2.exe
48249_to_49922 - 3 - Patch3.exe
49922_to_58414 - 4 - SP1.exe
58414_to_61388 - 5 - Hotfix 4.exe
Note... step 4, the install of 49922_to_58414 - 4 - SP1.exe takes a very long time.
My computer is fairly quick and that step alone took well over an hour.
All toll... install time is an all day job.
Then comes the wake up call. Your not done yet. Fixing errors and missing dependencies will
take quite a lot of additional time. How much depends on your skills at fixing or finding what is missing.
In my case, as stated, its been an all day job.
Good luck...
-AL