There are 45* and 37* fittings, yes. Parker says that their fittings will seal on either.
I have only had to use 45* fittings specifically, in a few instances myself, but the biggest priority here, IMO, is the ID of the hose and fittings.
I have seen some hydraulic applications where they didn't seem to worry much about a restriction caused by a fitting, I assume because they were using higher pressure.
I would think that this system would show more influence from smaller factors.
As far as the white corrosion and rust happening on fittings as
@nvrenuf talked about, I have seen it on hydraulic lines which were exposed to a lot of moisture on the outside. (Mixer trucks and equipment) I don't know what would reduce it much, but I have used anti-seize on the threads occasionally to try and help. Possibly a placebo effect there, however.