Generating lots of Necromancer Towers

I miss the old bug where you'd get like 20 necromancer towers on a map. I understand that getting that many might not be possible anymore, but I'd love to see how far I can push. I tried tinkering with World Gen parameters, but the best I managed was 4 towers after generating dozens of worlds (and hundreds more rejects). Which isn't that much more than you might normally get anyway...

Any tips?

Here's the parameters I was toying with (made these back for v34, might need to be updated for v40?)

[WORLD_GEN]
    [TITLE:NECROBOOSTED]
    [DIM:65:65]
    [EMBARK_POINTS:1324]
    [END_YEAR:1050]
    [BEAST_END_YEAR:100:80]
    [REVEAL_ALL_HISTORY:1]
    [CULL_HISTORICAL_FIGURES:1]
    [ELEVATION:1:400:800:800]
    [RAINFALL:0:100:101:101]
    [TEMPERATURE:30:70:101:101]
    [DRAINAGE:0:100:101:101]
    [VOLCANISM:0:100:101:101]
    [SAVAGERY:0:45:101:101]
    [ELEVATION_FREQUENCY:3:2:0:1:0:1]
    [RAIN_FREQUENCY:1:1:1:1:1:1]
    [DRAINAGE_FREQUENCY:1:1:1:1:1:1]
    [TEMPERATURE_FREQUENCY:1:1:1:1:1:1]
    [SAVAGERY_FREQUENCY:1:1:1:1:1:1]
    [VOLCANISM_FREQUENCY:1:1:1:1:1:1]
    [MINERAL_SCARCITY:2500]
    [MEGABEAST_CAP:4]
    [SEMIMEGABEAST_CAP:9]
    [TITAN_NUMBER:3]
    [TITAN_ATTACK_TRIGGER:80:0:100000]
    [DEMON_NUMBER:22]
    [NIGHT_TROLL_NUMBER:11]
    [BOGEYMAN_NUMBER:11]
    [VAMPIRE_NUMBER:11]
    [WEREBEAST_NUMBER:11]
    [SECRET_NUMBER:1000]
    [REGIONAL_INTERACTION_NUMBER:22]
    [DISTURBANCE_INTERACTION_NUMBER:22]
    [EVIL_CLOUD_NUMBER:11]
    [EVIL_RAIN_NUMBER:16]
    [GOOD_SQ_COUNTS:1:16:0]
    [EVIL_SQ_COUNTS:100:500:0]
    [PEAK_NUMBER_MIN:0]
    [PARTIAL_OCEAN_EDGE_MIN:0]
    [COMPLETE_OCEAN_EDGE_MIN:4]
    [VOLCANO_MIN:0]
    [REGION_COUNTS:SWAMP:0:0:0]
    [REGION_COUNTS:DESERT:0:0:0]
    [REGION_COUNTS:FOREST:0:0:0]
    [REGION_COUNTS:MOUNTAINS:0:0:0]
    [REGION_COUNTS:OCEAN:0:0:0]
    [REGION_COUNTS:GLACIER:0:0:0]
    [REGION_COUNTS:TUNDRA:0:0:0]
    [REGION_COUNTS:GRASSLAND:0:0:0]
    [REGION_COUNTS:HILLS:0:0:0]
    [EROSION_CYCLE_COUNT:250]
    [RIVER_MINS:5:5]
    [PERIODICALLY_ERODE_EXTREMES:1]
    [OROGRAPHIC_PRECIPITATION:1]
    [SUBREGION_MAX:2750]
    [CAVERN_LAYER_COUNT:3]
    [CAVERN_LAYER_OPENNESS_MIN:0]
    [CAVERN_LAYER_OPENNESS_MAX:100]
    [CAVERN_LAYER_PASSAGE_DENSITY_MIN:0]
    [CAVERN_LAYER_PASSAGE_DENSITY_MAX:100]
    [CAVERN_LAYER_WATER_MIN:0]
    [CAVERN_LAYER_WATER_MAX:100]
    [HAVE_BOTTOM_LAYER_1:1]
    [HAVE_BOTTOM_LAYER_2:1]
    [LEVELS_ABOVE_GROUND:15]
    [LEVELS_ABOVE_LAYER_1:5]
    [LEVELS_ABOVE_LAYER_2:1]
    [LEVELS_ABOVE_LAYER_3:1]
    [LEVELS_ABOVE_LAYER_4:1]
    [LEVELS_ABOVE_LAYER_5:2]
    [LEVELS_AT_BOTTOM:1]
    [CAVE_MIN_SIZE:5]
    [CAVE_MAX_SIZE:25]
    [MOUNTAIN_CAVE_MIN:4]
    [NON_MOUNTAIN_CAVE_MIN:6]
    [ALL_CAVES_VISIBLE:0]
    [SHOW_EMBARK_TUNNEL:2]
    [TOTAL_CIV_NUMBER:40]
    [TOTAL_CIV_POPULATION:15000]
    [SITE_CAP:350]
    [PLAYABLE_CIVILIZATION_REQUIRED:1]
    [ELEVATION_RANGES:136:272:136]
    [RAIN_RANGES:0:0:0]
    [DRAINAGE_RANGES:0:0:0]
    [SAVAGERY_RANGES:0:0:0]
    [VOLCANISM_RANGES:0:0:0]