Am I safe to top here? How do I tell?

And you're definitely going to want to top this strain...js

Yeah bud she's ready. If you wanna check out a topping I just did you can look at my lilac diesel diary. I topped her around week 4-5. Node 6. It's recommended to do it above the fifth node. I hope this helps.

Rule of thumb for most people is top it when it has at least 3 true nodes. I like cutting from 5th to 3rd node or just FIMing at the 4th

Yes, the place marked in your image is good. I think your leaves are a bit taco shaped, implying heat stress so try to adjust the lights