Only for sharing.
Here we use SAP B1 on Hana and SQL Server and it is like Frank pointed well: it does not meter the database option. It depends directly of how do you provide your WAN connection. Performance between both database are not so different.
You have not described exactly the way you want to use B1 over WAN and what version you want to provide to the users. Depending on, what you want to deploy and from where to where, there are a lot of discussions, decisions and attention points that you have to take care about.
I invite you to double check the guide "Hardware Requirements Guide for SAP Business One", item 2.4.2. Here is the link to this guide to B1 version 9.1:
https://websmp205.sap-ag.de/~sapidb/011000358700000244612011E.pdf
The item describe the network consumption as:
"Each concurrent user who is accessing Citrix or WTS sessions via WAN requires 0.5 Mbps (512 Kbps) external bandwidth.
Example:
For 32 concurrent users, an external bandwidth of 16 Mbps is required.
Network latency, screen resolution and other factors might impact Citrix or WTS sessions. Contact your solution provider for configuration details."
This is not exactly absolutely true. You have to experiment your needs to decide the best network bandwidth that fit you requirements.
Network also depends on where you want to dispose the application. A small example: your servers are on Unite States and you want to let users access them from Africa. You need to know the network web to know exactly how your user reach the servers. It is a fundamental information to let you decide well.
We use B1 over wan, we learned a lot to let user happier with the solution. And this was a hard process because there is difficult to find out the information you need. Even from SAP.
Citrix is more secure than WTS. Is also provides you some nice features, like map the local machine units on dialog box like save and open. It also consumes less network bandwidth comparing to WTS. It also let you configure the ICA protocol to tune the users experiences. But you need to be ready to pay the price.
We also do not get acceptable performance over networks with latency higher than 250 ms.
Do not forget to study the way your addons works. The document share and utilization strategy. There are many situations that can ruin your B1 on WAN and it do not depend the product you are using to provide the terminal emulation to your users.
If you provide more detail about what are your goals, we can to let this discussion more deeply. But we can only help you. At the end, you need to test the solution and ask your users if the solution fits their needs.