Managing space on an alley dock

The problem I'm having is I'm training in a FL,and have to test in an international truck(slower steering).
The practice course has only barrels,the test site has a complete trailer blocking the 11 o'clock position (NE),during my setup.
I have been setting up close to the middle of the road,Dot bumper at N corner,of one trailer N of my parking spot.
Then HR and HL to set up my trailer into spot,once I get the trailer started into the spot,(close gap on drivers side),I would pull up to the right and straight line back into the space.
I'm thinking this is maximizing both front and rear space for my maneuver.
Should I be more forward to make lining up trailer easier,then trying to get more trailer into space before doing my pullup?
I only have two more tries before sending me home with a CDL but no employment.
Why they train in a different truck than you test in is a mystery to me.
Both trucks in the diagram are the same vehicle,and once I clear the obstruction,I get another 6-8 feet of available space in front.
Thanks for any help you can give.
Just to be clear,12 o'clock is facing east,space is at 6 o'clock,I'm at 10 o'clock when starting my HR and HL.

 

Thanks for the help...this is how I'm thinking of setting up using the slower turning truck,before making any backward adjustments.With the FL I would be closer to the parking space,closer to center of road.
With the slower turning truck,I'm thinking more of what the photo shows.sorry about the lousy photo...Bad with paint.

View attachment 80646

 

If I step off my truck from the front,10 paces gets me exactly to the center space between my drive axles,another 10 paces puts me at the center of my trailer,another 10 paces puts me exactly at the dot bumper.
10 paces= about 25 feet.
5 paces=about 12 feet.
I haven't measured the practice site or the test site yet.
I've only practiced the maneuver for a few days,and I know you guys are probably thinking I'm over thinking the whole maneuver,but I have nothing else the whole weekend to study.
Thanks again for any help you could offer.

 

On my first attempt,I was too shallow,and before I could start over,another truck pulled in to do their test...wont do that again,I'm going to have to learn to fix whatever situation,I get myself into.I can see the angles well,and am starting to judge the truck better,but with only a few weeks training,only a few days on this maneuver,I'm just trying to get the best setup possible.

 

You get as many get outs and pull ups as necessary,but a 15 minute time limit,makes using too many a penalty.
I don't have any problems getting out,as my main concern is getting it parked safely.
One thing I've noticed is I can now perfectly eyeball 12,25,and 75 feet.
Thanks for the suggestions.