Scores on the GMAT Prep practice tests are more reliable indicators of how you will score on the real GMAT than scores on test prep company practice tests. So, that 730 is a decent indicator of how you will score on the actual GMAT.
Regarding taking another test, you probably shouldn't take another one too close to your actual test. You are better off giving yourself time to recover a bit. So, if you haven't taken another practice test yet, and you feel like taking one, today would be the day to take one, not tomorrow.
Regarding whether you should worry taking a confidence hit if you take another practice test, I tend to say to be aggressive and take practice tests without worrying about that issue. If you are worried about that issue, you already have confidence issues. In any case, the way to hit your score goal is to practice, not back down.
Be sure to continue prepping tomorrow. Sometimes people recommend sort of forgetting about the GMAT the day before your test, but the truth is that you are better off continuing with prep so that you are in game mode on test day. Don't wear yourself out prepping, but do continue to prep.
Also, warm up on Saturday. Don't wear yourself out answering dozens of questions or doing a huge amount of other GMAT related stuff, but for sure do a bunch of questions before you take the test to get into game mode, so that, when you see the first question on the test, you are already ready to go.