Recurring Trips from SEA-LAX. Need advise!!!

Hi Guys,
I will be having some recurring trips from Friday night to Monday early morning from SEA-LAX. Wanted some advise in booking the tickets from the pro's -

Will be traveling back and forth beginning Sept 20 through the end of the year.

Fares for the weekend travel - Leave SEA late friday (after 7pm); leave LAX early monday (latest by 8) are around $205-$250 on Delta (and United).

Award travel redemption in Economy for the same flights is 25000 miles + $5 (taxes). Is this a good redemption rate for (non-stop) flights b/w SEA-LAX?


Have following miles:
138,000 (Delta)
380,000 (United)

The fares/mileage redemption rates are pretty much the same on both United & Delta. Save mileage for international trips or long distance? What would you guys recommend?

Thanks,
Nitin