Congrats man. Now that you are getting comfortable upside down try a back roll. I think the progressive is easier than the mexican. Just throw your lead shoulder up and away from the boat and hold on to the rope. The boat does all the work for you. Easier than a tantrum in my opinion.
I also landed my first tantrum a week and a half ago. Landed my second one yesterday. I definitely love the feeling! it took me forever to get over my fear of backflips, and it was great to finally ride one out.
Its funny I started off trying back rolls last summer and felt my technique was way off because I was doing some weird twists, and then tried the tantrum instead.
Now that I have the tantrum down I think Im going to approach the back roll with the same mind set as the tantrum and hopefully land that as well.