Depends on the shop. I try to only have one or two heavy narrative write-ups maximum per day. If I can do the easy post office or other easy narrative shops in a day, that's different. I have done 4 post offices (4 max a day per guidelines), and added a non narrative food shop and a gas station or smart iPhone/Android shop, I can get in 8 - 10 shops per day. As for route shopping, that's different. That's when you let the MSC know you're route shopping and may need a little more time for the write up or ask them to accept the shops you've applied for in a certain area.
Get to know your schedulers. If you see a route forming, let them know. Say I will only do shop "A" if I can also do shops "B, C, and D" in the same area, if not, I can't do shop "A". Believe me, the schedulers will work with you if you do good work.