Custom Expressions with Common Metrics

Hi all - newbie here!

Is it possible to use multiple common expressions in a single custom expression within the query builder? I’ve built one common metric for ‘Sales’ from my order table, and one metric for ‘Sessions’ from a web traffic table - and ideally I’d like to use these two to create a conversion rate metric.

Is this possible? If not, is there a way to use multiple distinct count metrics in a calculation?

Thanks in advance!

I’m also wondering about this. As soon as you want to combine metrics are you forced to move into SQL? Doing division on metrics to get percentages seems like something that many users would want to do, is this possible?