`x = 54, y = 64, rule = B3/S23`

bo$2bo$3o5$4bo5bo$5bo5bo$3b3o3b3o11bo$24bo$22b3o$26bo$26bobo$26b2o2$

16b2o$7bo7bo2bo$7b2o7bobo$6bobo6b2obob2o$17bo2bobo$17bobo3bo$18bo5bo7b

2o$23b2o7bobo$32bo6$26b2o$25b2o$27bo3$49b2o$48bobo$48bobob2o$47b2obobo

$49bo2bo$49bobo$25bo8bo15bo$24bo7b2o$15bo8b3o6b2o$14bo$14b3o$12bo$6bo

3bobo$4bobo4b2o$5b2o2$21b2o$17b2obobo$18bobo$15bo2bobo$14bobobob2o8b2o

$15b2obobo9bobo$17bo2bo9bo$17bobo$18bo2$5b2o$4bobo$6bo!

EDIT: #276 from a 15-bitter:

`x = 280, y = 47, rule = B3/S23`

187bo$187bobo$187b2o6$167bo$77bo90b2o$78bo88b2o$76b3o$67bobo$68b2o23bo

bo$68bo11bobo10b2o72bo6bobo$25bo55b2o11bo8bo61bobo6b2o$23b2o56bo19b2o

63b2o7bo$24b2o76b2o$19bo94bo121bo$8bobo6b2o94bo123bo$9b2o7b2o93b3o39bo

79b3o$9bo143bobo97bo$17bo61b2o73b2o95b2o$18bo59bobo171b2o$11bo4b3o60bo

49b2o28bo15b2o68bo$10bobo115bo2bo25bobo15bo2bo26b2o32b3obobo3b2o$11b2o

89bo4bo20b3o27b2o16b3o26b2o34bo2b2o3b2o$24bo78b2obo133bo$obo21bobo12b

2o3b2o38b2o16b2o2b3o19b3o45b3o24b4o40b4o24b2o$b2o4bo3b2o3b2o6b2o12bo2b

obo2bo36bo2bo40bo2bo44bo2bo20b2o2bo2bo40bo2bo23bobo$bo4bobobo2bobobo

21bobobo2bo11bobobo20bo2bo40bo2bob2o9bobobo23b2o2bo2bob2o17bobobo2bob

2o10bobobo19b2obo2bob2o19bo2bob2o$7b2ob2obobo24b2ob2obob2o30b2ob2obob

2o34b2ob2obobo38bobob2obobo20bob2obobo35b2ob2obobo20b2obobo$12bo2bo29b

o2bo2bo27bobo3bo2bobo32bobo3bo2bo40bo3bo2bo20bo3bo2bo40bo2bo22bo2bo$

12bobo30bobo2b2o19bo7bobo3bobo3bo31bobo3bobo40b2o3bobo20b2o3bobo41bobo

23bobo$13bo13b2o17bo24b2o7bo5bo5bo31bo5bo47bo27bo32b3o8bo25bo$21b2o4bo

bo40bobo18b2o148bo$21bobo3bo212bo$21bo6$156b2o$97bo57bobo$96b2o59bo$

96bobo!

EDIT 2: #336 from a trans boat on cap:

`x = 107, y = 30, rule = B3/S23`

80bo$78bobo$79b2o3bo$82b2o$64bo18b2o$65bo21bo$63b3o21bobo$87b2o2$19bo

50bo10b2o$20bo50bo9b2o$5bo12b3o3bo44b3o29bo$6bo6b2o7b2o11b2o4b2o32b2o

4b2o17bobo$4b3o5bobo8b2o10bobo2bobo2b2o28bobo2bobo2bo14bobo2bo$3o9bobo

b2o19bo2bobobobo6bobobo19b4obobobo12b2obobobo$2bo10b2obobo16bobo2bobo

2bo29bobo2bobo2bo14bobo2bo$bo15bo17b2o4b2o32b2o4b2o17bobo$69b3o29bo$

71bo9b2o$70bo10b2o$9b2o$10b2o75b2o$9bo77bobo$87bo$12b2o69b2o$12bobo67b

2o$12bo66b2o3bo$8b2o68bobo$7bobo70bo$9bo!

EDIT 3: Much farther along for one of the #269 predecessors:

`x = 215, y = 27, rule = B3/S23`

7bo$6bo61bo$6b3o58bo58bo$63bo3b3o54bobo$bo62b2o7bo51b2o4bo29bo$2bo60b

2o6b2o57bo28b2o$3o3bo65b2o52bo3b3o27b2o$5bo62bo30bo26b2o25bo24bo$5b3o

59bo29b2o26bobo26b2o22bobo$19bobo45b3o28b2o53b2o23b2o$19b2o23b2o30b2o

17bo13b2o23b2o27b2o21b2o25b2o$10b2o8bo22bobo29bobo17b2o11bobo22bobo23b

2obobo17b2obobo21b2obobo$9bobo28bo2bo18bo9bo2bo18bobo2b2o3b2o2bo20b2o

2bo24bobobo20bobo24bobo$6bo2bo5bobo15bo5bobobo16bobo8bobobo23bobo2bobo

bo20bobobo24bobobo15b2o3bobo21bo2bobo$5bobob2o4b2o17bo4bobob2o16b2o8bo

bob2o25bobobob2o16b2obobob2o20b2obobob2o14bo2bobob2o19bobobob2o$3b3obo

bo6bo15b3o2b3obobo26b2obobo27b2obobo17bob2obobo21bob2obobo17b2obobo21b

2obobo$2bo3bo2bo8bo17bo3bo2bo28bo2bo22b2o5bo2bo21bo2bo25bo2bo19bo2bo

23bo2bo$2b2o2bobo8b2o17b2o2bobo29bobo24b2o4bobo22bobo26bobo20bobo24bob

o$7bo9bobo21bo31bo24bo7bo24bo19bo8bo22bo26bo$102b2o47b2o19bobo$101b2o

47bobo20b2o2b2o$103bo69bo2b2o$153b3o22bo$153bo$60b2o92bo$61b2o$60bo!

Roughly the second half is taken from the double griddle synthesis.

EDIT 4: Finally solved #269 from a 17-bitter not on the list:

`x = 33, y = 25, rule = B3/S23`

28bobo$28b2o$29bo2$15bo$16b2o$o14b2o$b2o5bo21bo$2o7b2o13bo5bobo$8b2o

12b2o6b2o$23b2o2$5bobo8b2o9b2o$6b2o7bobo9bobo$6bo9bo10bo2$17bo$13b2obo

bob2o$13bob2obobo$17bo2bo$17bobo$18bo$5bo$5b2o$4bobo!

EDIT 5: #278 from 13 gliders and nothing else:

`x = 30, y = 37, rule = B3/S23`

29bo$27b2o$24bo3b2o$bo20b2o$2bo11bo8b2o$3o9b2o$13b2o$6bobo$7b2o$7bo$bo

bo$2b2o$2bo15bobo$18b2o$19bo5$18b2o$13bobo2bobo$14b2o2bo$14bo6$10bo$8b

obo$2o7b2o$b2o$o$20bo$9b2o8b2o$10b2o7bobo$9bo!

EDIT 6: #139 from a solved 17-bitter:

`x = 110, y = 35, rule = B3/S23`

41bobo$42b2o$42bo2$46bobo$40bo6b2o$41bo5bo$39b3o$56bo6bo6bo$56bobo3bo

5b2o$6bobo47b2o4b3o4b2o$7b2o9bobo67b2o$2bo4bo10b2o68b3o2bo$obo16bo67bo

b2obo$b2o84b3o2b3o$88bo$84bo$6bo13bo34bo28b3o$4bobo13b3o3bo23b2o3b3o3b

o25bo16b2o$5b2o10bo5bobobo23bo6bobobo23bo2bob2o10bo2bob2o$17b5obob2o

24bob4obob2o24bob2obo11bob2obo$22bo17b3o9bo4bo29bo4bo11bo4bo$19b3o20bo

11b3o32b3o14b3o$9b2o8bo21bo11b2o14b2o17b2o15b2o$10b2o57bobo$9bo48bo10b

o$58b2o$57bobo$62b2o$15b2o44b2o$16b2o6b2o37bo$15bo7b2o$19b3o3bo$21bo$

20bo!

EDIT 7: #260 from a 12-bitter, in a similar style to #336:

`x = 122, y = 31, rule = B3/S23`

95bo$96bo$94b3o3bo$18bo54bobo14bo7b2o$16bobo9bo45b2o15b2o6b2o$17b2o8bo

46bo15b2o$22bo4b3o$20b2o$21b2o56bobo$80b2o$80bo$14bo33bo45bo22b2o$bo

11bobobo7b2o14b2o4bobo37b2o4bobo20bo2bo$2bo9bobob2o6b2o15bobo2bobo2bo

35bobo2bobo2bo18bobo2bo$3o9bobo5b2o4bo16bo2bobob2o12bobobo20bo2bobob2o

17b2obob2o$4b3o6b2o5b2o19bobo2bobo38bobo2bobo21bobo$6bo34b2o4b2o38b2o

4b2o21bobo$5bo111bo$80bo12b2o$22b2o56b2o11b2o$14b2o5b2o56bobo$13b2o8bo

$15bo$101b2o$11b2o11b2o74b2o$10bobo10b2o77bo$12bo12bo70b3o$15b2o79bo$

15bobo71b2o6bo$15bo74b2o$89bo!