SkyMiles tickets can be booked no more than 331 days in advance of travel.
Award redemption rates can be determined from the interactive award travel map: from 100K miles coach r/t, 150K miles business r/t. No SkyMiles redemptions may be made for intercontinental first class with Delta miles. If you're being quoted something other than Low band mileage it is due to Delta travel to/from the TN gateway: all partner travel is Low award band (HA* oddities discussed elsewhere).
One can find coach and business awards LAX-PPT with ExpertFlyer that should be available for immediate booking.