I recently bought the 390 Boss Bindings and I'm riding the Northwave Decades. When strapped in, I noticed that there is some space between the highback and the boot because of a little "bump" on the back of the decade (see pictures).
The problem is that I do not know if this is gonna be a problem or not. In my old bindings (Forum Platform 1.8) the boot directly "connects" to the highback with similar forward lean, because the highback is not that straight from the bottom to the top.
I do ride a quite decent forward lean, when I put the highback to 0 degrees on the Rome, the effect is even worse and there are about 2 cm between boot and highback. I am still able to return those bindings even the first impression on building quality etc. is really good. Not really sure what to do, input well appreciated!