Check this out and see if it ties in with your experience
Basic Row Order:
33, 20, 19, 22, 15, 24, 12, 26, 10, 28, 8, 30, 18, 21, 14, 23, 11, 25, 9, 27, 29, 7, 6, 5, 4, 3, 2, 1, 17, 16, 31, 32
However it had a few caveats.
(a) If you booked a middle seat and are one the party the other two seats beside you will go right to the top of the queue.
(b) If you book two seats in a single row the remaining seat in your block of three would be put at the top of the queue
When Ryanair originally started assigned seating, (a) and (b) did not apply, however because people were being separated these caveats were put in place to make it less likely that children and parents would be separated. Therefore seats with no free seat next to them are always allocated first for solo travelers.
So therefore the true priority for solo travelers was
Single seats in 33, 20, 19, 22, 15, 24, 12, 26, 10, 28, 8, 30, 18, 21, 14, 23, 11, 25, 9, 27, 29, 7, 6, 5, 4, 3, 2, 1, 17, 16, 31, 32
THEN
If there is no single seats, any seat in 33, 20, 19, 22, 15, 24, 12, 26, 10, 28, 8, 30, 18, 21, 14, 23, 11, 25, 9, 27, 29, 7, 6, 5, 4, 3, 2, 1, 17, 16, 31, 32
Therefore your very best way of checking in to get seats next to you used to be 32C and 32D.
I was told this by Cabin Crew!
Unfortunately it is certainly different now, because when checking the seat-map I'm seeing 31 and 32 gone a lot with the majority number of premium seats at the front of the plane not filled where previously 31 and 32 you could bet on always being there.
By the way, caveats (a) and (b) still apply to this day, it's just the order of the rows that has changed.