New columns will be added as the last column. You can easily rearrange the columns in the SQL Spreads Designer by grabbing the small handle and move the new column to the desired position:

It is possible to setup a connection to multiple SQL servers with SQL Spreads?

Yes, if you use separate Excel documents. The SQL Server connection in SQL Spreads is per Excel document, so to connect to two different server you will need to use two separate Excel documents.

When using the Advanced Mode in SQL Spreads you can customize your import SQL query to use a linked server in SQL Server and in that way import data from two different servers into the same Excel document. All Database Mappings has to be to the same server.

Can I set a default value on a column in SQL Spreads?

To use default values in columns when you insert rows from Excel to SQL Server, you will have to add those default values on the table in SQL Server. 

To add a default value to a table column in SQL Server follow these steps:

1. Open SQL Server Management Studio and connect to your SQL Server instance. 
2. Locate your table and right-click the table name. Then select Design option in the menu shown:
   
3. Select the column for which you would like to add the default value. In the Column Properties window below your columns, enter your default value into the field Default Value or Binding:
   
4. Click Save to save the changes to the table

Does SQL Spreads supports linked server?

Linked servers is unfortunately not supported in SQL Spreads. Though, you can connect one Excel document to one SQL Server and then connect another Excel document the another SQL Server.