Im currently at 83%. I would like to give you a tip on the One Make win trophy. Basically start race in 16th (dead last). Work your way up to 2nd and stay close to 1st on last lap. Very easy for me on the Corvette one make race with a full powered C7 Stingray. Get near 1st, staying neck and neck and within the last few hundred meters of the finish line, nudge ahead just beating the 1st place car. Might even get the 0.01 trophy too.
BTW, the 0.01 trophy is a bit easier than some might think. I actually got the trophy to pop by getting 0.08, so they give you a little slack. Or it could be glitched lol. Hope this helps.
On a side note, compared to GT5, this platinum seems far more accessible for me. The only ones that are giving me issues right now are the darn S-license golds.