Hello @Greg243,
The "Dates unavailable by default" setting means that dates are not available for booking unless you manually unblock them. They being available or not for booking doesn't in any way depend on price setting. You could select this setting, set your prices as far in advance as you need to and then manually unblock dates for which you've set your desired price and on which you can accommodate guests.
With this option you can receive bookings as far in advance as you have manually priced and unblocked dates.
You can still use one of the time based options but set prices for the available and as yet not available dates which are further in the future than the number of months you selected. In time, as those dates become available, the price will be the one you set while they were still marked as unavailable.
With this option you can price dates as far in advance as you wish but bookings will be possible only up to a rolling 12 months in the future, 6 month or 3 months depending on which specific one you choose.
Steve.