Tricker's Bourton Fit/Sizing Help (Gaping)

[wingtipbrogues]

BACKGROUND:
Decided to sell my go-to brogues (Loake 1880 Chester) purchased 3 years ago because for some reason they feel too small these days, perhaps they were always the wrong size and my feet is just less tolerant these days. Either way I am using this opportunity to upgrade to some Tricker's, but need some advice with sizing.

Photos on imgur

FACTS:

• Always considered my feet to be pretty average, not particularly wide or flat
• Never experienced gaping before in my other shoes either (Grenson Toby/Stanley, Loake Aldwych)
• Tricker's Woodstock derby 9.5 (last 4497S) is a good fit for me, no gaping

Bourton 9 (if taking the common advice of sizing down)

• Length is good, has a slight amount of initial heel lift that feels right (if that makes any sense)
• Width feels slightly more snug than my ideal fit
• Overall more comfortable than the Loakes

Bourton 9.5 (if staying with usual size)

• Length is still ok (more but still acceptable amount of heel lift)
• Width is good, toe box is comfortable with good wiggle room
• Is showing clear signs of gaping, even worse when thicker socks are worn

FIXES ATTEMPTED SO FAR:

• Insoles to improve arch support - did not resolve gaping
• Heel cushions - did alleviate gaping, but not sure what comfort levels will be like in the long term

I usually don't wear thick socks very often, which is why the size 9 is still under consideration. But I am wary of thinking it will eventually stretch to an ideal fit, because I think that was my initial mistake when I bought the Loakes. Am hoping this gaping issue doesn't mean I have to give up on the Bourtons as it is such a great shoe both in look and build.

Thank you.