Where is the first quote from, Stirling? Can't find it on my end.
This type of out-of-context, isolated translation is something I'm all too familiar with
from my first year in university, and not something that actually helped me internalize
the various meanings of the subjunctive and optative, although that's just my experience.
The optative by itself without the particle ἄν in non-subordinated clauses
expresses a future wish or desire -- ex. may she come here tomorrow
-- and it may be preceded by
εἴθε/εἰ γάρ, the difference between the aor. and pres. opt. being that of aspect,
not tense, as explained by others above. (Smyth 1815
To express an unattainable desire or wish, if it refers to the present -- ex. I wish she would (now)
, with the implied opposite but she isn't
-- the imperfect is used and here εἴθε/εἰ γάρ
must be written. If it refers to the past -- ex. I wish she would have been here (yesterday, the other
with the implied opposite but she wasn't
-- the aorist is used. (Smyth 1780