A mechanical oblique is deficient in two ways:
1) Its stroke contrast distribution is warped: the relationship between the horizontal and vertical parts of the letters is unnatural (or at least unconventional).
2) Its structures are not sufficiently cursive, for example in the "a" and "g". Some people think this is critical, others think it's not but it's still nice to have structural differences between the roman and italic, to help their differentiation when the latter is used for emphasis in a body of the former.

The more you shear, the more #1 (and maybe #2) becomes an issue. I've made a font with a ~3.58 degree shear, and it required minimal correction. Your 6 degrees is probably borderline.

But the less you shear, the more #2 become important (for differentiation).

I guess saving money by making your own fake italics can make sense, but know that it's a compromise, not just in terms of craft quality but also function: a Helvetica slanted by only 6 degrees will not function well in a body of the original upright font (unless you also use a different weight, or less likely a [slightly] different size).

Here's another idea: don't use italics. Let saving money be the trigger, but make ideology your justification, and use gentle weight gradations for emphasis instead - it's purer. Check out Typo magazine to see how that's done:
http://www.magtypo.cz/

BTW, please say hi to Barcelona for me.

hhp

Generally I agree with Hrant that mechanical obliques are deficient. However, in the case of Helvetica it should be noted that the usual Type 1 Helvetica package actually uses the slant function of Type 1 to make the italics, so you are actually paying for the same upright font twice, once with the slant set to the italic angle and once with it not.

Really? Sheesh. What's the angle, 12?

hhp

Yes, 12 degrees.

When I was working on Helvetica Linotype, I had to make my own italics, because the Type 1 source data didn't exist. I corrected the curves slightly, but didn't want to differ too much from the sloped roman with which everyone was familiar.

Thanks guys. I used Hrant's sugestion of emphasis through bolds and it worked really well. Thanks guys!

Cool. PDF?

hhp

Sorry, I would but I can't since the project I did- just a practice on before working on the portfolio is for a familly friend's business, and I don't want to put their info on line. I appreciate the imput though and am sorry I can't share the end result..