The small wedge is supposed to be 15 degrees. I don't know what your Rossi's are rated, but the forward lean numbers are about at useless as flex numbers when compared between brands. Many of the new boots are claiming sub 15-degree lean. After years of skiing my Krypts with the big wedges (17 degrees) I decided to "modernize" my skiing and switched to the small one reducing my forward lean by 2 degrees. This felt like a huge change and required about 15 hours of skiing to really get comfortable with it, and a modification of the way I had been skiing for most of my life. It took a lot of time to make them work in the bumps. Even though I finally made them work at an "acceptable level," and I felt like I was using less leg muscle to ski, I eventually abandoned it because I did not like the loose connection to the front of my boots with the upright stance. A more upright stance allows you to use more skeleton and less muscle, but may not be the best position for skiing variable conditions and terrain.
The progressive flex of the Krypts facilitates a weight forward more hang on the front of the boot neutral position that I love, and I believe can only be achieved with a 3-piece shell boot. Regular 2-piece shell boots do not have a progressive flex so they have an on/off feel that is hard to get used to when coming from Kryptons, and I believe this is exaggerated by a more upright stance. I suggest experimenting with loosening the top buckle and tightening the Booster Strap to allow you to hang a little more into the boot with your stance and soften the hair trigger effect of leaning into the boots. I cannot over emphasize the difference in feel between the Kryptons and regular 2-piece shell boots, and it takes time to transition. You actually ski them differently with the Krypts using more knee action going forward as opposed to the Rossis skiing like most boots and initiating by hinging more with your ankles.
Ramp angle and several other factors can effect the situation, but after years of messing with differenct boots and forward lean I have come to the conclusion that your body type and natural style dictates a certain optimum forward lean. You can learn to ski any boot, but buying one without adjustable forward lean may trap you into needing to adopt a new style.
I am not a boot fitting expert and have probably not provided any answers for you, but hopefully it is some usable food for thought that will help you dial in your new boots. The heel lifts actually make you sit back more, which would make it more difficult to engage the front of your boots, and the spoilers help support you back there, so without them your quads would burn, but those do not sound like "healthy" adjustments. You probably need to see a good boot fitter, or just keep skiing the new boots until it becomes more natural.