Banner will be 32x79in. I am using adobe Illustrator (for the first time) to design this. I heard to cut down the document size, but still be accurate scale, put a . in between. So 3.2x7.9. Now, I am trying to determine which font size to use for title and subheadings. Any help is very appreciated!
To answer your question, just move the decimal over like your file sizes. 200pt becomes 20.0pt, 65.5pt becomes 6.55, etc.
You should build the document at 100% full size. If the file needs to be big, then it needs to be big. If you build it at 1/10th scale, you'll have to use 10x higher raster settings so that it is not pixelated when enlarged. Doing that will cause the file size to increase to essentially the same amount anyway, so you're better off working at full size.
About the only file size difference gained by working at a smaller scale is from the full sized preview. The scaled document has a smaller preview, and is therefore slightly smaller. The tradeoffs and possible math / resolution mistakes far outweigh that small benefit though.
I think my snapshot will help you to choose the size of the text.
In general You can use the size of text as below.
• For Hedding - 170pt to 210pt • For Subheader - 110pt to 130pt • For Body Text - 60pt to 100pt
Other than that the Logo, Images or Icon sizes depend on your design.
I think this will help you to get appropriate size in during designing. let me know if you have any concern.