What stem do you intend to use? If it has stack height in 40mm range, look at Syntace Flatforce which is 27mm, that's about half an inch, should be more than enough. Other manufacturers should have similar products too, like FSA SL-K -20deg. If stem's not enogh, you can save about 1mm by swapping upper bearing to FSA SL ACB, I did that recently and had to add 4x0.3mm spacers so stock Neco dust cap doesn't rub the frame.