I don't see any reason not to use P(OPh)3 if that's what the literature prescribes; I used several hundred mL without trouble this week (to make triallyl phosphite; way cleaner than going from PCl3, FYI).
I would just correct a couple of points from above:
1. It's not pyrophoric. At all. You can measure it in a measuring cylinder. Incidentally, I am not aware of any phosphites that are, although I'm not an expert.
2. It's not going to boil---boiling point is 360 °C which is almost the same as that of PPh3, even though the latter is a solid.
3. I doubt that it would azeotrope with thionyl chloride, which has a boing point almost 300 °C lower. Can't think of any azeotropes that span that difference in boiling points. I didn't struggle to distill triallyl phosphite and allyl alcohol away from it this week.
4. Can't think what relevance cone angle and pi acidity have here. I mean it's not like the thionyl chloride is back-bonding the phosphite; we just care about pure nucleophilicity to sop up "Cl+"-type impurities.
If you've got a literature reference for doing this, I would trust that more than us randoms on the internet. No point taking a risk if you have the reagent and the procedure. I'll also note that this is a method described in The Purification of Laboratory Chemicals, which is normally pretty solid.