You def want your toes and heel to be completely snug. Proper boot fitting is really difficult, especially since boots continue to expand with use. J-bars are a great idea, also smartfeet. I'm guessing that because of your heel lift, you've overtightened the outside of your boots thus smushing your toes? The liner is what should be tight, the boa or laces just reconfirm
You'll want your heel to sit tight down on your boot, toes snug, but not hurting. Once you strap in, your bindings will set your foot back and will relieve some of the pressure from your toes. But for sure do something about the boots. If you take them to a shop, they can try a couple different things for you, but if your heel lift persists, you should look in to a different pair of boots. I know this from experience, I have a toenail that has been black all season (the beginning of the season i suffered way to long with heel lift, and by the time i switched boots, the damage was done). Now said toenail has completely fallen off as of yesterday.
Every turn is a blessing.