Level 5 and above in Prato Toscano

I'm usually able to achieve 5 star gold without boosts for all but the very most insane episodes. However, starting at session 5 in PT I'm having difficulty -- it's a matter of coins, not of serving all customers since I do that regularly with time to spare. I have all food upgraded 100% and decor/equipment upgraded up to just below the levels which add customers.

Maybe it just can't be done without those extra components (I'm not even sure boosts would help since its not a matter of not serving customers or of serving low quality dishes) but I'm wondering what other people have experienced.

I haven't completed those additional upgrades because I've not yet completed the whole season and I didn't want to make the final few episodes impossible for me to complete by adding even -more- customers! I do realize that I can complete the season as is, then make additional upgrades and conquer the season again. I was just, as I've said, interested in other people's experiences.