Ya it is quite an obnoxious large switch- I have the same on my '68. You'll have to fabricate something or look through Holley's accessories. They do make some bracketry for stuff like that. Or you might find a Mr Gasket or similar aftermarket set up that you can adapt. Something like a universal throttle cable mount that could be adapted. Just make sure to mount the little pad on the carb correctly so that it clicks the switch under WOT. Make sure it doesn't impede full throttle movement.
You can drive without it in the meantime but will have to drop it manually in the meantime.