I wish I had known the answers when I began transitioning from Hobbying to Sugar Dating, so let me briefly try to answer your questions. In the future, just put one question in your post. You'll get more answers.
The ones who just say Hi are trolling for responses. Usually they will correspond with you if you reply. But I do find a short message like that, or Hello Handsome, kinda frustrating. Those asking for your weekend plans may be pros in disguise, but again, you never know.
I do have a protocol that works, but won't go into details here and now. A first meeting for coffee is what I always expect, although a few SBs have said let's skip the coffee date and go somewhere private right away! Others have met me for coffee and then gone directly BCD. But most have met me for coffee, then our first BCD date was a few days to a week later. I always offer to meet for coffee, sometimes lunch, never a fancy restaurant that costs real money.
How much I typically pay is gonna be less than your big city rates from what others here have reported. I pay $200 to $250 per date, which makes it much less expensive than Hobbying. No clock watching, and the gift is always given AFTER the date activities are concluded.
Finally, yes, the Sugar Bowl has it's share of sharks. I always seek out the regular girls who just want to have some fun with an attentive respectful guy who will give them a few bucks.
Hope this is helpful! Let us know how your dating goes!