I'm getting a new frame and hoping to fit big tyres on the front. The forks can take a maximum of 40c
Get a fork which actually fits the tyre you want, and if necessary get a frame whose geometry works with the chosen fork.
You've done the first step of bicycle selection right by thinking about tyres first, so now carry it to its logical conclusion.
If you bolt the hub to the fork in any position other then the one it was designed for, you will be loading the fork ends, and possibly the axle, outside their design parameters. There isn't a lot of spare metal in fork ends.
Get a fork which actually fits the tyre you want, and if necessary get a frame whose geometry works with the chosen fork.
You've done the first step of bicycle selection right by thinking about tyres first, so now carry it to its logical conclusion.
If you bolt the hub to the fork in any position other then the one it was designed for, you will be loading the fork ends, and possibly the axle, outside their design parameters. There isn't a lot of spare metal in fork ends.