Agreed , go along and test , my personal favourite is the 200 - 2stroke , more than enough power , light weight but yet I still feel in control , I raced a 200 in regional enduro's and changed to a 450 , it took me about 8 months before I started getting the same results as I was getting on the 200 , the 450 while great was just too tiring so the first half of the endure I would do ok and then get progressively slower , on the 200 I would have a difference of 1 to 2 minutes over a 45 to 60 minute lap between my fastest and slowest lap .
So maybe for a novice the 200 - 2 stroke or 250 - 4 stroke , I find the 250 - 4 stroke just a bit more hard work in very slow riding , but in low traction situations they score big time .