| Dear Devin,
As per my little knowledge of astrology the pointwise replies are as under:
1) In case of email the time of opening of email and in case of SMS time of reading of SMS is to be taken as time and place is to be the place of the astrologer, However in case the email if the writer has put the date and time at the top of the email then we have to take the time,date and place given on the email.
2) Place will be the place of the prasan karta.
3) It is difficult to have 8 to 10 questions in a lagan untill and unless you have particular time of answering them i.e. if you sit in your office say from 7pm to 9pm in that case we have to take arudhya lagan.
4) Yes, anybody can receive question on behalf of astrologer, but he has to write time,place and date of the query.
Hope this will suffice your queries. You can also refer to Book on Prasan by Shri Deepak Kapoor it is in 2 voloumes and replies any query in mind you can think.