In the papers The periodic Floer homology of a Dehn twist, Rounding corners of polygons and the embedded contact homology of $T^3$, and Combinatorial embedded contact homology for toric contact manifolds, Hutchings and Sullivan, and Choi, use an interesting trick to dismiss the existence of pseudoholomorphic curves counted by the ECH differential. That is, they are in a Morse–Bott degenerate setting, so they perturb the contact form to get only two "non-degenerate" Reeb orbits (an elliptic and a positive hyperbolic orbits) for every foliated tori, and they do this for all tori with "energy" less that a fixed $L$, then make this $L\rightarrow \infty$ and you get a sequence of contact forms converging to the initial one (See page 9 of Choi - Combinatorial embedded contact homology for toric contact manifolds for example).
Anyway, to do this perturbation in every such torus, Morse functions in $S^1$ are required, they are carefully chosen so that the (only two) extremal values of the function are at "specific" places; this "specificity" is made clear by parametrizing the space of Reeb orbits in any such foliated tori (see (57) in Lemma A.1 of Hutchings and Sullivan - The periodic Floer homology of a Dehn twist and the proof therein for example).
It happens that in such a perturbative setting some necessary conditions can be found for the pseudoholomorphic curves counted by the ECH differential to meet, however some of the curves satisfying these conditions can actually be eliminated of the count by perturbing in "the right way" and by this I mean using the specific choices of the Morse functions.
Now, here are my questions:
This seems to work only when our contact 3-manifold is the product of three 1-manifolds (or at least is like that up to a pair of Reeb orbits, because I know $S^3$ and the lens spaces, can be treated in the same way, see Choi - Combinatorial embedded contact homology for toric contact manifolds for example). Can this be recreated for more general cases, for example a case where the 3-manifold is "piece-wise" $I\times T^2$ (for example, three of these pieces) and these pieces meet at critical levels where there are other Reeb orbits, not contained on foliated tori?
Is there a more general technique for dismissing existence of Pseudoholomorphic curves? I have seen the papers Hutchings and Taubes - Gluing pseudoholomorphic curves along branched covered cylinders I, Hutchings and Taubes - Gluing pseudoholomorphic curves along branched covered cylinders II on obstruction bundle gluing, which in theory, could always be used for dismissing or proving existence of pseudoholomorphic curves in the symplectization of 3-manifolds setting. The way I see it, proving that $G(u_1,u_2)=0$ (see Hutchings and Taubes - Gluing pseudoholomorphic curves along branched covered cylinders I page 9 for the notation) for a pseudoholomorphic building with levels formed by $u_1$ and $u_2$ should imply the non-existence of pseudoholomorphic curves (with certain properties in relation to the ends of the building) near the building. So, could this be effectively used for a specific problem? For example, could we redo the result in the first three papers with this idea instead of using the parametrization of the Reeb orbits in a foliated tori? I asked this because there are cases in which this parametrization cannot be attained in global coordinates nor will cover all Reeb orbits, for example, the orbits outside the $I\times T^2$ pieces. Notice that indeed, the gluing papers came like four years after the papers on PFH and ECH of $T^3$, so the idea may not be far-fetched.