I've made a checker now, I think the config matches your criteria:

{"challenge": [

"define 'dt' as expression difficulty*1000 + terrain*10.",

"with name '2/4' find 8 caches where dt == '2040'.",

"with name '2/4.5' find 8 caches where dt == '2045'.",

"with name '2.5/4' find 8 caches where dt == '2540'.",

"with name '2.5/4.5' find 6 caches where dt == '2545'.",

"with name '2.5/5' find 8 caches where dt == '2550'.",

"with name '3/4' find 8 caches where dt == '3040'.",

"with name '3/4.5' find 8 caches where dt == '3045'.",

"with name '3/5' find 8 caches where dt == '3050'.",

"with name '3.5/4' find 8 caches where dt == '3540'.",

"with name '3.5/4.5' find 6 caches where dt == '3545'.",

"with name '3.5/5' find 8 caches where dt == '3550'.",

"with name '4/4' find 8 caches where dt == '4040'.",

"with name '4/4.5' find 8 caches where dt == '4045'.",

"with name '4/5' find 8 caches where dt == '4050'.",

"with name '4.5/4' find 6 caches where dt == '4540'.",

"with name '4.5/4.5' find 6 caches where dt == '4545'.",

"with name '4.5/5' find 6 caches where dt == '4550'.",

"with name '5/5' find 4 caches where dt == '5050'.",

]

}

As a side note you may want to change the colour you use for highlighting the numbers on your page (or outline them as well) I'm colour blind and found it very hard to distinguish between the green and brown (or whatever colours they are!)

As a second side note it looks like either I've made a mistake in my interpretation or GEO FISCH doesn't actually qualify.