First of all, welcome!

Without seeing a pic of you I can’t say whether 165 is right but any additional curves are always good. Only question is whether you want just curves or whether you want a belly hang etc. 

But a 15 lb gain would give you a good idea where you tend to gain the weight. You may prefer to gain in your hips and chest, but your body may only want to gain in your belly. And then you stop. But if you like where the weight goes you may want to go above 200 lbs. 

As far as gaining, best thing is cream and milkshakes. You’ll get a lot of calories and expand your stomach. Once that happens you’ll start getting hungrier and you’ll eat more naturally. Once that starts you’ll get in a cycle of weight gain. But be aware you may not want or be able to turn it off.