75 is a great temp for cresteds. you don't want it to get much above 82 or so for any extended period of time or it is actually harmful to them. unless it gets really cold where you are keeping them--below the mid 60s--you probably don't need the heat pad at all.

to help tame them you can try feeding them crested gecko diet or baby food by hand. when mine are babies i put a little dab of it on their noses and when they start licking it off i hold up a little baby sized spoon for them to eat out of. this helps them get used to you and lets you know that they are in fact eating.