The safest way is to get axles with that spacing. For the front, you could do a Willwood disc brake conversion and get the proper lug spacing that way. You wouldn't need adapters then.
When I was ordering my rear end from Strange and my Alter-k-tion, I thought about this because it seems like you can find Chev lug pattern wheels everywhere and they are usually cheaper for used ones because of the prevelance.
If you like the wheels that much and want better discs in front I would go that route. Having the axles made and redrilling the rear drum would be the cheapest part of the pattern swap.
If you go with spacers, they aren't as safe. They would push the wheels out further, possibly too far to use, hitting the fenders. You will probably extend you track by 1.5" or more. Don't know how the offset on the WS6 wheels are.