Look at 61.109(c) and there may be differences in the maneuver section of the Practical Test Standards.
https://www.faa.gov/training_testing/testing/test_standards/media/FAA-S-8081-15a.pdf
I don't know about Helicopter but I know that fixed wing you'll be aksed to demonstrate ground reference maneuvers which are not taught in EASA- land. For fixed wing add 3-4.5 hrs to adequately train those.
Since you'll be asked to demonstrate navigation skills some XC instruction would be appropriate.
I'm guessing you'd be closer to 10-12 hrs before the practical test can be taken.
This is where it gets important you choose a school that has experience with foreign licenses and are familiar with the differences.
Don't go to one of these "Hi Y'all c'mon in" places as it could get frustrating if you fail a PTS task on a test which you didn't know about and the Instructor assumed you did as you already hold a PPL(H).
Now it's personal opinion time so be warned
Since the subject in question has the funds to purchase a N-reg Jet Ranger I wouldn't skimp on training.
That's a serious machine.
I'd recommend to do all the required training and the exam flight on a Jet ranger.
And they go for $1000/hr.
Money doesn't buy you skill.
However money can buy you training which can get you the skill.
As a former flight instructor I've dealt with my share of affluent students and some we've had to turn away as they were simply not willing to undertake the required training in order to be safe, not just legal.
It always amuses me seeing somebody who is not willing to even spend 10% of the purchase price of their toy on training.
A miserable 10%...to keep them safe.
I'll just leave this here:
http://www.bbc.com/news/uk-scotland-glasgow-west-14803595