opposite happened for me, I gained room and a great fit from box stock.  I just heated them for the first time on Saturday.   when I first tried them on they were quite tight on my big toe.  I'm also generally a 1/2 size smaller then what I bought.  They fit perfect now after heating them.

you need to stuff rolled up paper towel in the toes during the heating process and leave them in there when you pull them out.  Radar manual says toe caps, but try finding them!  also I think the extra room the paper towel gives will pack the liner out a bit more, so will actually using them, just like shoes they will pack out over time.

I found by the time I got the liners into the shells I could put them on no problem.  the heat was not an issue at that point.

I only wore the liners for about 10 minutes & they were done.  once they're cool they're done.

try it again with the paper towels.  you should be able to heat them at least 4-5 times and get a different fit out of them every time in my experience with heated liners on alpine ski boots.

also don't heat them up too much.  you only need about 200f for 10 minutes.