Alright, here's what you've gotta do.
1st: Just an idea, but if you're at like a cat skiing lodge or something, find a ledge after skiing with some powder under it and just try backflips. You can't land a backflip if you don't even know what it feels like.
Jump: When you build the jump, you want to build one with a really steep lip. I learned backflips on a really steep lip, a lot of my friends did, it's just the easiest way to learn because, by the time you take of, the jump's already done half the work for you and so you don't have to throw it as hard. In that case, make the lip probably like near veritcal at the very top. Not completely vertical, but probably like 60 or 70 degrees (i take you have a slope gradient thing since you're catskiing in the bc). Also, 4.5 feet high (you could always go bigger if you want) is probably where you should shoot for in height and just make sure the landing is soft/powder in order to give you a bit of confidence in case you land on your head. This should get you up high enough to throw you around and will make doing the trick even easier. It may sound a little bigger than want you have, but when it comes to inverts, air is your friend and will give you more time to correct mistakes.
Technique: Alright, so when you go to hit this bad boy, do this. First, speed check. Go off it a couple of times just straight to get the feel of the jump. If you built it right, you'll find that straight airing it will be kinda difficult because the jump will really want to kick you backseat and you may have to fight to land square on your feet when you hit it straight. Once you've done this once or twice and are comfortable with and have a feel for the air you're getting, go for it. Come in at the same speed as you did straight airing it, knees bent, eyes on the jump. When you're onto the lip, pop and take your arms and throw them forward and up and simutaneously kick your head back like you're trying to look at your ass. This will arch your upper body back, initiating the flip. Also, judge how hard you do this by how much time you were in the air when you speed checked (This is one of the reasons trying a backflip without skis is kinda important). Once in the air, KEEP LOOKING BACK. This is where people usually bail and land on their head. To commit is to keep looking back. Do it. When you get inverted, you will then able to see your landing and judge how far you are from landing. If you're too high and spinning too fast, then tuck you're legs back like you're doing a backscratcher. If you're too slow, pull your knees into your chest. (p.s. the tucking/laying out part may be a little advanced for you right now, but once you get the hang of these, that's how to check your rotation speed). Either way, keep spotting that landing. By this point, the tricks then pretty much over. As you keep looking, your legs will naturally come around below you and you will touch down for landing. Easy as cake.
Now, alll in all, I really elaborated on how to do this trick, but bottom line, it's probably one of the easiest tricks out there (USASA (no homo) rates backflips the same pointage as 180s for that reason). Its really all about committing and timing you're spin and physics does the rest after that. It honestly doesn't matter what skis you use either. Yeah, your Toons may be a little slower to get around than some of your other skis, but if your in pow, they'll probably make landing the easiest and I doubt you'll really notice that much of a weight problem with them. In fact, my homie learned his backflips on 189 AK Enemies with Axial 200s because his park skis were broken and now that he's got tons of inverts in his bag, he says that backies are really no different whether you've got heavy or light skis. And they're not. So, just take those Toons, build that jump, sack up, and huck and tuck. You'll be $$.
