I'm an engineer dabbling in chemistry as well. If you're looking to etch copper, you can make copper chloride or ferric chloride(iron(iii) chloride). I can't really see a reason to combine HCl and H2SO4 because it won't really do much. In fact, in my experience aqueous HCl dilutes the H2SO4 making it weaker.
Peroxymonosulfuric (H2SO4+H2O2) oxidizes diamonds to CO2 under the correct conditions, and will probably do the job, but if that fails Peroxydisulfates are known etchants and can easily be produced electrochemically.
Peroxydisulfuric acid(H2S2O8) can be prepared via anodic oxidation of H2SO4 and can be reacted with aqueous ammonia to produce Ammonium Persulfate which is an excellent etchant.
I'm not sure what you're trying to etch, but I think the Peroxydisulfuric Acid and/or it's conjugate bases should do.
Oh, one more, Aqua Ragia (HCl +HNO3) dissolves gold, so that's another option.
I hope I was able to help.