Gus has faster hands, is more technical and a very good counter puncher and moves well. JDS has never fought a boxer like Gus at HW and there are no fighters at HW with Gus's boxing, counters and handspeed.
I think JDS has good power to put Gus on his ass but I think the fight would be competitive and Gus has better movement than JDS, faster hands than JDS and has a very good chin.
JDS can do what he does at HW in terms of striking because he is faster than everyone else but in this fight he would be the man with the slower hands and movement but power.
I think the fight would be competitive and if JDS cant knock out Gus, I see Gus winning by decision. HW has never been anything special but slow strikers and slow fighters with power. I dont think JDS does as well with his striking at LHW with the faster strikers and fighters. If CroCop can touch up JDS with straight left hands in their fight, Gus will find a home.