10/10 Timmy. That looked great and there's nothing i wouldn't have done there except obviously if you're not gripping he could have just let go of you and you would fall off.
But still it worked and yes there's some vulnerabilities with bjj techniques one being that you usually have only one posting hand to rely on for a base and the other is that with all your weight on their upper body they can lift you out of small dojos easily.
Which is why i say if possible you want to grab a leg to secure any armbar or guard but it wasn't necessary in your case.