I would try to do a ‘1st meet’ soon, providing all was well, you could start the 129F process with the proof of meeting. As far as flying over, long way, some expense, 30 days is a long stay. Long stays cost more $$.
Why not go soon, get the proof of meeting, then fire off the 129F application? Since the 14 pages of the application takes a while, start it now, fill in parts later of meeting.
One should get a feel for the relationship, if for some reason it turns south, you can opt out later by not completing required steps.
Some suggest getting married is a viable choice, then coming to the USA, maybe. For me I settled on the 129F.