I keep on getting this profile gauge in ads on youtube, but it looks like its not a bad idea as its bigger than the normal ones you find and adjustable.

www.smartsaker.com/pages/saker-contour-gauge-8?gclid=CjwKCAjwwMn1BRAUEiwAZ_jnEgVzPqYcvRhOSqPSkz1SVn5Ww6u9dFdzkk8kKBFzsrIQLlH3olEhrRoCLiAQAvD_BwE

I think someone was talking about using these types of things to get board rails the same.

Yep that was me.....

I have one the same, just a bit shorter. These things are awesome for board rail profile.
I'd like to find one wider (ie: the pins can move more)
They're pretty expensive, but this is priced well and a bit longer so that link is very helpful to anyone building boards

I've just ordered the 10" version, should be great for delta style fins