Dessert bar quantity

It depends on the size of the portions.

"In terms of quantity, think of it this way — it’s always better to have more food than not enough, and that goes doubly for desserts! A good rule of thumb from Sweet and Saucy Shop is:

For a table full of mini-desserts (no cake), allocate about 3-4 mini-desserts per person. (Editor’s note: take this down to 1-2 mini-desserts per person if you’re also having cake.)You don’t want to overwhelm guests with options, so choose 2-3 more options than what you’re allotting per guests. For example, if you are assuming 3 mini-desserts per person, you should have about 5-6 dessert options.

That means if you’re having a dessert table and a wedding cake for 100 people, you should have about:

2-3 servings (including cake slices) per person, or about 250 dessert servings total.4-5 different types of desserts to choose from"

My FSIL had a dessert bar as part of her favors and it was phenomenal. It depends how it will be set up honestly. She was lucky enough to have staff at her venue running dessert stations including:

-ice cream station with all the toppings imagineable
-cake station with 6 different kinds of cake
-pie station
-crepe station
-popcorn and hot pretzel station
-donut station
-cannoli station
-beignet station

And then she had tables where guests could box up their own candy, cookies, brownies, cupcakes, etc. She had 175 guests at her wedding and I would say there was even too much food. If you’re not able to have stations, I would try to get things people can easily take like cookies, brownies, cupcakes, donuts, mini pies, etc. and for 150 guests I would order 300 of each to give guests the option to take two or more.

Get mini everything that way it won't seem like you are a crazy person ordering tons of sweets. And with baggies they can take leftovers home so you won't feel wasteful, let's face it there will be leftovers.