Sure thing, on a standard brannock device you can measure your foot from heel to toe, heel to ball, and the width.
The "absolute" length of my foot is a size 9.5 on the brannock device. This is the heel to toe length.
The slider on the device for arch length, which is the heel to ball measurement of your foot is a 10 for me.
In either a 9.5 or 10 I wear a D width.
I find that a US size 10 has a little too much room for my whole foot, but my ball is in the correct location in the shoe. A 9.5 places the ball a little forward of optimum, but the length is better overall, thus I wear a 9.5D.
Can you give me any guidance as to the JL 7000 last and what might be a good fit for me?