I had a GM rep tell me that exact thing..was very $$ as well for them as far as offshore goes..ive found that there is no fix really aside from leveling the hood pegs..when I purchased the chrome kit it comes with a plasic chrome cap...had to really turn these suckers in to make them fit..hood needs a good slam to latch it..fits tight..keeps the gap uniform anyway..my gap is prob quarter inch atleast..buff the paint on the underside and its not so noticable..as far as the adjustment bolts they only move ya forward and back..no real way to "pull the hood down" more and if you try to adjust the fender too far the goofy clips on the front bumper wont line up very well anymore..best off just get the gap staright and live with it then spend hours frign around to get nowhere fast...

As I already said, I have seen some that fit nice but it appears to me at this point ya pretty much have to pull the front down with the latch as far as reasonable .. then level side to side .. and live with the results.
I am looking here to add another HHR to my inventory so I am just going to put a Priority on this one to make sure I am comfortable with the way it fits before I buy.
If I didn't like these little cars so much I wouldn't waste my time with all the issues they have.

Hood to fender; Top CLEARANCE
 

Ah, I had the same problem, (Until TODAY!)
I thought I'd see if I could pull up on the fender flange, then I noticed a pair of larger holes on each top fender flange leading to other "pilot holes."
I loosened the few 10 mm mounting bolts, and used an old G. M. type jack handle/lug wrench inserted into these holes and pried up with the handle, then retightened the bolts, I raised the top of my fenders almost 1/4".
It is the fenders that will move up to reduce the clearance gap.
Man it looks a lot better NOW!
Not a lot of adjustment on the hood hinges, that's for sure.....

Finally ... Someone with a new solution and also linking the issue directly to the fenders not the hood.
Not that everyone is going to go to those lengths to fix it but "Cudos" for your extra efforts.

After 8 HHR's I have finally settled on a 2010 1LT 2.4 auto.
It only had 14,500 miles on it when I bought it 3 months ago. and the fenders and hood fit close and even on both sides.
They look so much better when the gaps are not there especially on certain lighter colors that show the dark gap areas.

Silverfox