To be fair to Trump people were pretty sceptical when he took over Doonbeg, it was a world class course and people locally were worried how it would turn out. As most golfers who visit the place will tell you, they left the course pretty much as it was and made some changes but only to the hotel/food & beverage side of things. The course is still a great play. The main ''go-to'' guy in Ireland and Scotland for golf tours is still that Dave Henry guy from henrygolf and he maintains Trump Doonbeg is still a premium course.Having said all of that I shot one of my worst ever rounds there....!!!
Don't worry about offset. Focus on how the clubs perform for you. Look at launch, flight and spin, feel at impact, sound and looks.
Offset is just a part of head design that includes a bunch of dimensional measurements and mass characteristics used to optimize launch and spin.
Think of it as where are the puting the center of gravity of the head. Lower and further back (offset) changes launch. Slower swing speeds need a bit higher launch to optimize distance.