Biased turkey
I could tell you that I got the gold in Seattle2 and the GT40 at the 2nd trial but ... I would be a liar .
I'm proud to announce that I just got my S license ( bronzes ) last saturday.
If I remember it took me between 1 and 2 hours for each test, except for Seattle2 - GT40 ( 8 hours ) and Monaco-GTone ( 4 hours ).
I could maybe have reduced the time if i had realised sooner that traction and stability aids were on. my times improved a lot ( by at leas 1 second ) after I turned them off.
I used automatic transmission and the gamepad.
3 weeks ago I was able to get all gold in the b licenses using the gamepad for some and the driving force for others.
I'm not your average GT3 player either,I'm 55 years old . I feel like the Mario Andretti of GT3

I decided to finish my S license and try to get all gold in b licenses after visiting the GT Planet GT3 forums.
Biased "oldtimer" turkey
Well my story is kinda simular to the one Biased Turkey wrote, I am little younger though

. I did not even know I could switch off ASM and TCS and only used automatic (AT) and an old PS1 controller without the pressure sensitive buttons. And I did not know about GT Planet
I also was new to the game of GT, so after failing the bronze time in the wet circle tests after trying for hours I cursed the game and left it in the box for a month at least. Later I took it up again and it was such a good feeling to pass this test I picked it up again up to the S Licenses.
It took me more time than I care to remember to pass S2 and S6. When I reached S8 I literally gave up on the game, I cursed the developers who put (in my opinion at the time) an undrivable car in a required lesson without any option to change the setup. After that I stopped playing GT3 for at least 6 months. My problem was that using AT and a PS1 controller I could not keep the car from spinning and ruining every run.
It was not untill I saw a review of GT Concept (or a tip somewhere) that GT Concept awards you the bronze licenses, which I went out to buy and did get the bonus licences in bronze (I had only S8 left, this was how bad I wanted the super license to race the remaining races).
Just 2 days after that I discovered GT Planet and I read the tip to use manual in S8. Within three succesfull runs I had silver (PAL version)
Now I could finally go for 100% completion, which I have done twice now and also hunted for the gold medals for a while. I am at 42 gold and 6 silver (S2/S3/S5/S6/S7/S8) at the moment. There is a thread by Daan in this forum with the best S-License replays so I probably will get inspired to try for the remaining golds.
Now I am playing GT4 Prologue a lot and guess what I love the licenses (all gold by a large margin). There are some reasons for that:
a. the gold times required are a lot easier to achieve
b. improving your time netts you points (crazy but for me this is an incentive)
c. the tests actually make sense, you do learn the basics of driving different cars and the specific racing lines in a course. Also the racing lessons where you have to overtake other cars are great, much better than any of the GT3 license tests.
So if you ask me, are the bronze license requirements in GT3 too hard? My personal answer is yes, they did take the fun out of the game for me a newby to the game at the time, for at least 7 months. I am not saying that the required bronze times are set too high but without the knowledge and proper equipement they aint fun at all.
My 2 cents