Pardon my ignorance, but I don't understand your post (no pun), and despite 40+ uears in the bike industry, I've never seen or heard of a seatpost that doesn't allow saddle angle adjustment.

By quill post do you mean one which expands at the bottom, rather than depending on a frame pinch bolt as most do?

If so, most of these are of the plain pin type, and take saddle clamp assembly at the top. Saddle clamps allow almost 360° of saddle adjustment, from almost vertical, nose down to the same, nose up.

If OTOH you mean that your current post has an integrated saddle clamp, but the range of adjustment is too limited, then your option is to buy a plain pin post and clamp, or a different I-clamp post such as the old Onza post which allow for a larger range of adjustment than most. (however may not be available in the right OD for your frame.

If I haven't addressed your problem, please clarify exactly what it is, and I or others may be able to point you in the right direction.