In a WT article in 1943 July , I think pages204-206 The "Lord" told told them the hours for pioneers, aux pioneers and publishers. The "Lord" changes his mind-how many times do these hours need to change? Anyway, a search will find the archived WT and you can read for yourself what the "Lord" told them.
I found the reference, thank you!
WT 1943 jul 1 "RIGHTEOUS REQUIREMENTS"
"These expressions of God’s will by his King and through his established agency constitute his law or rule of action for the “faithful and wise servant” and for their goodwill companions today who will dwell upon the earth for ever in the New World. The Lord breaks down our organization instructions further and makes them more practicable by further instructing us through his “faithful and wise servant”. He says, ‘Let us assign the field, the world, to special pioneers, regular pioneers and companies of Jehovah’s witnesses in an orderly way, sufficient for everyone to thoroughly witness therein, and let us place upon each one the responsibility of caring for the New World interests in these respective assignments.’ He says the requirements for special pioneers shall be 175 hours and 50 back-calls per month, which should develop into a reasonable number of studies; and for regular pioneers 150 hours and as many back-calls and studies as can be properly developed during that time. And for company publishers he says, ‘Let us make a quota of 60 hours and 12 back-calls and at least one study a week for each publisher.’ These directions come to us from the Lord through his established agency directing what is required of us; and, for those who really love the Lord and are guided by his counsel, that is a reasonable service requirement. This expression of the Lord’s will should be the end of all controversy. It is for your good that these requirements are made; for thereby you are enabled to prove your integrity and magnify the Lord’s name."