Adding screen printing to home embroidery business

I have a home embroidery business and am looking to add a screen printing business. I have read all the posts about how time consuming & messy and learning all the tricks takes time. I have never even seen a screen printer in person so newbie is an overqualification. I work at a school and can get the business from them and other schools. I'll have all summer to practice. I will work from home, buy a used press and definately will take the 2-3 day training. My questions are:
1.Which press would be best
2. which ink is best
3.Should I buy new or used equipment?
4. What kind of software for designing t-shirts is economical yet offers a wide range of designs.
5. Should I condiser a DTG instead?
6. I live in the heart of OK where humidity is 100% most of the time, does that matter?
7. Can 2 people do 100 shirts a day?
Thanks in advance for your help!

Location: 
United States