heads up you can trade after the first gym, not the e4, unless you're on about transferring from previous gens.
I haven't finished my HGSS run, but I have noticed that HGSS's level curve and the amount of grinding pre first e4 (and for a good bit after) is... really bad. may be worth trading them over for grinding (boosted exp) which isn't cheating at all as long as both copies of the game are legit and you've got two different consoles ofc
don't forget to grind for thunderbolt at the game corner early in the game - it's OP, definitely on magnemite and ampharos (I personally suggest the former for your team - magnetometer works really well)