Good Day Lylyhannah,
Thanks for posting.
Could you please ensure that your are updated to the latest version of PlusSpec (V18.8.0)? To update, please click on the following link (https://plusspec.com/release-notes/
), sign in and follow the prompts to install PlusSpec. You update PlusSpec the exact same way as when you installed PlusSpec the first time.
After updating, in the Wall Tool dialog, the 'Single Masonry' wall type was designed to be used for materials like bricks, blocks etc. and the thickness of the wall comes from the materials selected in the 'Materials, Selections & Finishes' section of the dialog. If you want to have different wall thicknesses that are available then they will need to create a material and enter the desired thickness.
Regarding added foundations to walls as you draw, this can be done by going to the 'Manual Overrides' section of the Wall Tool dialog, ticking the option called 'Footing?' and entering the associated values for the footing size & position under the wall.
Could you please try this and let me know how it goes?