To anticipate our results, it turns out that while the surrogate LM geometries are in general very close to their first-principles analogues for all lower-level methods considered here, the energy hierarchy varies significantly between PES approximations and can considerably deteriorate the search. Nevertheless, our results show that in combination with a state-of-the-art polarizable force field, the approach is highly successful in generating surrogate low-lying minima that match experimental structures for the two test case systems including two isomers of the protonated Gly-Pro-Gly-Gly tetrapeptide (referred as GPGG herein) and the doubly protonated gramicidin S cyclodecapeptide. This encourages the use of sGADFT for a straightforward, fast and automatized way to identify lowest-energy structures of peptides in the gas phase.