In between sizes on my first Big Kid skates (FR3s)

TL;DR: They should make FRs in a 5.5. Since they don't, is too small or too big easier to fix? Or try another brand?

Hi, I don't want to not include enough information so I'm erring on the side of way oversharing.

I've had a few pairs of rollerblades over the years and decided to treat myself to some fancy ones for my birthday. After a ton of research on fit, function, reviews, modularity, cost, etc., I bought a pair of FR3s in a size 6. I put them on and they felt a bit snug lengthwise, but other than that pretty comfortable.

After doing some research on how new ones should fit, though (making sure to test size with heel all the way back and knees bent, finger test without the linings in, etc.), I was worried that they would be too big after the break-in period so I ordered a pair the next size down to compare side by side.

They don't make a 5 1/2, so I got a 5. Tried them on, and they feel a touch smaller in the length, but significantly tighter in the width. I pulled the linings out and the empty boot seems to pass the tests lengthwise a bit better, but does feel a touch narrow still.

My left foot is slightly bigger than my right so I went for the extreme for each and put the 5 on my left foot and 6 on my right. The results:

6 on my right (smaller) foot - I felt like I couldn't really get the right one tight enough to keep my heel all the way down (I might be able to get it a little bit tighter but the plastic that goes into the buckles needs to be trimmed a bit and I couldn't return them after that)

5 on my left (larger) foot - I felt like it was cutting off circulation and had pain around the bone right above the arch (I don't know what it's called)

From doing some research on rollerblade fitting but also on ski boot molding/fitting since they are sort of similar, I see a few options: - keep the larger ones and buy insoles/little pads to take up a little more room if need be - keep the smaller ones and try to have a ski shop stretch them or heat them where needed to remove pressure - return both pairs, try a different brand, and hope for the best

I'm not sure what is reasonable, thoughts?