I don't have any comparison pics of the actual produced Klingon minis to share at this time. However, I can tell you that you'll be pleased with the sizing.
The Klingon D-7 was scaled up a fair bit, to match its proportions in the original comparison drawings (from "tv"), etc. I'm one of the folks, like you, who always felt it was a bit too small (even the old Gamescience D-7 was too small) - this was addressed. She now masses about the same as the Fed CA, if not a tiny bit more.
The F-5 was also scaled-up, quite significantly and has a more long/lean design than the old, boxy mini. It looks at lot more like SVC's line art now and is sized to be the "biggest frigate or smallest destroyer" in the SFU.
The other Klingons all follow in-line with what was done to the D-7 and F-5 (since they mostly all use engines from those models).
This pic shows the size of the D-7, compared to the Fed CA and D-5:
This pic shows all the Klingons (at the time), compared to each other:
