If I got this right (and hopefully someone is double checking this) our worker will finish improving the second silver on turn 31. He would not be able to chop until turn 33. The slowest plan gets BW on turn 32 (in time for the first chop). Only Plan 2A could get a turn 31 BW and this is with working a coast tile instead of an improved sheep tile for a turn, but I don't really think we need BW on turn 31, unless we are going to be whipping something on turn 32. If we get BW on turn 32, we can whip as soon as turn 33.
I would recommend the third plan I mentioned above (it could be called Plan 3) since it gets BW on t=32 with a turn faster Work Boat
Here is Plan 3:
(an * indicates a possible unit build)
t=18 17/74 beakers (11 bpt); 2/24 food (6 fpt); 2/30 hammers (2 hpt) [imp'd sheep, unimp'd sheep]
t=19 28/74 beakers (12 bpt); 8/24 food (8 fpt); 4/30 hammers (2 hpt) [imp'd sheep, imp'd sheep]
t=20 40/74 beakers (12 bpt); 16/24 food (8 fpt); 6/30 hammers (2 hpt) [imp'd sheep, imp'd sheep]
[IBT]: Them grows to size 3
t=21 52/74 beakers (14 bpt); 0/26 food (7 fpt); 8/30 hammers (3 hpt) [imp'd sheep, imp'd sheep, unimp'd silver]
t=22 66/74 beakers (14 bpt); 7/26 food (7 fpt); 11/30 hammers (3 hpt) [imp'd sheep, imp'd sheep, unimp'd silver]
[IBT]: Mining researched, begin teching BW
t=23 0/179 beakers with 6 overflow (14 bpt); 14/26 food (6 fpt); 14/30 hammers (5 hpt) [imp'd sheep, imp'd sheep, plains forest hill]
t=24 20/179 beakers (14 bpt); 20/26 food (6 fpt); 19/30 hammers (5 hpt) [imp'd sheep, imp'd sheep, plains forest hill]
[IBT]: Them grows to size 4
t=25 36/179 beakers (16 bpt); 1/28 food (5 fpt); 24/30 hammers (6 hpt) [imp'd sheep, imp'd sheep, plains forest hill, unimp'd silver]
[IBT]: Work Boat is built, start Warrior*
t=26 52/179 beakers (24 bpt); 6/28 food (6 fpt); 0/15 hammers with 0 overflow (5 hpt) [imp'd sheep, imp'd sheep, imp'd silver, unimp'd silver]
t=27 76/179 beakers (24 bpt); 12/28 food (6 fpt); 5/15 hammers (5 hpt) [imp'd sheep, imp'd sheep, imp'd silver, unimp'd silver]
t=28 100/179 beakers (24 bpt); 18/28 food (6 fpt); 10/15 hammers (5 hpt) [imp'd sheep, imp'd sheep, imp'd silver, unimp'd silver]
[IBT]: Warrior is trained, start Warrior*
t=29 124/179 beakers (21 bpt); 24/28 food (5 fpt); 0/15 hammers with 0 overflow (7 hpt) [imp'd sheep, imp'd sheep, imp'd silver, plains forest hill]
[IBT]: Them grows to size 5
t=30 145/179 beakers (24 bpt); 1/30 food (4 fpt); 7/15 hammers (8 hpt) [imp'd sheep, imp'd sheep, imp'd silver, unimp'd silver, plains forest hill]
[IBT]: Warrior is built, start Settler*
t=31 169/179 beakers (28 bpt); 5/30 food (0 fpt); 0/120 hammers (13 hpt + 4 fpt) [imp'd sheep, imp'd sheep, imp'd silver, imp'd silver, plains forest hill]
[IBT]: Bronze Working is researched
t=32 0/? beakers with 18 overflow (28 bpt); 5/30 food (0 fpt); 17/120 hammers (13 hpt + 4 fpt) [imp'd sheep, imp'd sheep, imp'd silver, imp'd silver, plains forest hill]
I can put up the numbers for other options if people want to see them.