His words:
maybe 10% that should make it over the second leg
I think he implied that you calculate the fuel required with relative accuracy, then just add a 10% excess for the needs and go with it. (as oppose to refuel completely and attempt going out heavy)
Keep in mind those birds on full belly will give you 6000+ nm range, but from KPIR to KPDX you only looking for 1000+
Noting that is what he reffered as "empty" -- in constrast to a full load.
BTW... Had you tried landing and taking off the A332 from KPIR? The A330 family is very kind on that respect: but in any case is not as large as the B748.
Still, if we stick by the numbers
https://en.wikipedia.org/wiki/Airbus_A330#Specifications
And considering we are not ASL, but 2000 ft above, the runways at 7000 ft happen to be short of your needs to lift with MTOW.
(fun to try out thou )