Maybe I should start with this: there is nothing wrong with structure_start and structure_end. It is just that after working with SQL for awhile, using SQL-view, SQL-triggers and sometimes stored procedures become a thing. That will all be picked up by SQL examiner, but it surely not the only way to go. If you don't do that yet, structure_start will be fine to use.

MS-SQL favors performance and reliability over disk space. If it is a problem for you, you can set the recovery model to 'SIMPLE'. That way you can have a 0 MB Log file. It also means you can not recover the database. Not a good trade off if you ask me.

Like 3 years ago I got an emergency call from a customer when I was at home. Nothing worked anymore. Their web shop didn't work, their warehouse didn't work anymore. Back office didn't work. Some excel sheets (the ones that used SQL), same story. Reason: hard disk was full. MS-SQL had simply come to a halt as it didn't have disk space anymore. Maybe cloud setups are more flexible, but only having 5 GB free is a big risk.

One last small thing: if disk space is important, make sure you are using varchar on the larger ascii-fields and not char. That is something that can make a big difference and has no downside.