If we have multiple site which have different html structure so what is the better way to implement scrapy?

should I create multiple spider according to site in single project?
should I create multiple projects according to site?
or another way, please define.
Different website - > different script in same project if scraping same data so in a same project both the scripts can reside and use the same pipeline
Same website - > Same project
Different website ,Different Data - > Different project
Same website, different data - > Use 2 functions using callback
what is the better way to implement scrapy if we have multiple sites?