I produced the Heil speakers for a customer who really had his heart set on the Heil AMT driver. I used a pair of Seas L22's with it.
In answer to your question, the Heil design, while certainly good, was not a match for the HT3's.
The Heils had the advantage of being able to cross lower than the G2 ribbon. But you needed woofers that would play high enough to mate with them. And, of course, there was no need for the W18 since the Heils performed midrange duties as well.
One drawback of the Heils is limited vertical dispersion, something that is not a problem with the G2 pure ribbon tweeters in the HT3's.
If I were to do that design again, I perhaps would use the Seas W22's rather then the L22's. But the budget did not allow for it.
I originally was going to offer the Heil design as a standard product. But it just didn't seem to fit in my line of speakers anywhere. The HT3 is a superior design and, for the money, the Veracity QW is a better over-all speaker.