I have the Alpinestar "Track" pants and theyre pretty much similar except for the knee pucks.....They both do stretch out and do get more comfy in time but in the begining, it feels like you wish you got once size bigger....
It took 3 days of all day riding for it to break-in for me but it fits fine now.....the past mix weather of hot days and fog seemed to help the process.....
At first, they were tight as hell and I'd get a wedgy going into every corner and looked forwards to the rides on the freeways instead....
I was afraid that I'd be the first BARFer to post about a crash cuz of too tight of a leather pants when riding....:laughing
The knee armor might need to be taken out or moved around a bit to help prevent it from irritating your knees which I had to do .....I took them out, stretched them open, folded the joints till it seems to flex more and then put them back in.....
Hope this helped but it doesn't hurt to go back to try on a bigger size as well just for a peace of mind.....
I had to try on 3 pants of the same size and 1 larger till I found one that fits me to my liking....just like any Levi's jeans, sometimes mass produced riding gear can fit differently even if marked at the same sizes.....
good luck.....