Ken, it sounds like you have a backfed breaker from your solar sub panel, so yes, you should be able to just put the solar CTs around those lines. This is my setup and what’s described in the Sense solar install guide.
Luis, I think you’re referring to a line side tap, which is less common but still done in some areas depending on the individual utility policies. You should have a junction box where your solar feeds in to your line side, between your meter and main panel. It may be possible to get your solar CTs in there, depending on the distances and space involved. I would definitely call an electrician for this, because anything on the utility side of your main breaker is hot all the time. Even by shutting off your main breaker and your solar disconnect, there will still be 220v in that junction box.
As Sense recommends… it’s best to call an electrician for any work in or around the main panel.