I tried the Hawk but I do not like the wide blade format, so the Hawk has remained ignored. I do have a large stock of DE blades, which makes the ECO more attractive as a candidate for modding, rather than putting effort into the Hawk with it's more costly blades, of which I do not have in stock in volume. I used the following link on shimming as my primary guide, paying close attention to reverse shims.Out of curiosity, did you try the Hawk too?
Are you shaving against the grain? I've used alot of DE's and never noticed much chatter, and sting has always been due to using too much pressure or wrong angle (riding the bar).It's very efficient, the chatter from the blade causes considerable sting from the AS though. Shims does reduce the issue, there's too much blade reveal.
I'm guessing your Merkur Futur is DE, since I don't think Merkur makes the Futur in SE, but maybe try breaking a Merkur DE blade in half, and stick it in your ECO before giving up on it??? I've read SE razors are more picky with blades than DE razors. I for one tried the ECO once and while there was chatter the cheap Derby blade I tried wasn't horrible, but I haven't tried shimming mine yet.OK, my final thoughts on the ECO. I've tried everything. Doubled up the blades, heavier handle (that did improve the shave somewhat, but not enough), different angles, etc. At this point, I've thrown in the towel. This is one rough shaving razor! I didn't get as much irritation as the amount of chatter while shaving would lead me to believe, BUT, the chatter was horrible. Truth is, I do like heavier razors but wanted to try a lightweight. I had used a few injector razors a long time ago and liked the way they performed so I thought I'd try the ECO. I'm done with it. Yesterday, I returned to my Merkur gold plated Futur and decided to try the Merkur blades in it. I can't believe the difference. The razor glided over my skin with no chatter or tugging, almost as if there weren't a blade in it. So, this was the first shave with the Merkur blades and it reminded me of the first shave with the British Wilkinsons many years ago when they were first introduced to this country through hardware stores. At this point, no more experimenting. I'm enjoying this Merkur combination too much to screw with it.