I want to buy a reversed eye rear leaf for my spring and Langs sells them for 26/27 cars and cars up to 25. Whats the difference in the spring?

Bruce W. McAlley who wrote the Encyclopedia from Ford sources didn't think the rear springs were different 1918-27, the lowering in 26/27 came from the higher arc in the rear crossmember.
http://www.mtfca.com/encyclo/S-T.htm#spring
Front springs differ though, there's a lower arc in 26/27 front springs.

I still don't think you need reverse eyes in your rear spring to lower the car - here are a few pictures of my low budget home lowering job:

Here's a front main leaf in the vice, messy workbench as usual.. Old exhaust pipe covers the leaf, it's used for leverage. I bend only a small amount in each step, then moves the leaf slightly in the vice. Note the english drop frame front axle leaning to the wall

Here the main leaf is straightened

And here it has it's new shape with the eyes reversed. Note the straighter part around the center hole - the risk of breaking the leaf is high at the center hole, so I let the center bolt pull the spring into final shape. The #2 leaf needs to be shortened.

And finally rear springs - a standard rear compared to a deformed spring I tried to save by bending in the vice to a lowered shape. About four inches lower was too much, got just about one inch of spring travel, but two - three inches shouldn't be a problem just by reshaping without reversing the eyes.

since there seems to be a wealth of knowledge here about lowering springs and im assuming speedsters. I have a 9 leaf rear spring ready to be installed in a car and need to know how many to take out of the rear and which ones? the speed handbook says the second to smallest and second to largest. is this good wisdom?

A nine leaf rear spring is a totally different spring than a 8 leaf. I'm not aware of there not being any interchangeablity. The Ford catalog says 09-27 on them.

looks like the main leaf is longer now, is it? and is it gonna be a problem if so?

Hi Mike, sure didn't need any spring expander to mount it, but it fit OK, problem was this one got lowered too much, got in contact with the axle housing too soon when loaded.. I'm fixing to reverse the trunk lid into a rumble seat, so the rear spring can't be softened by removing leafs like on regular speedsters. I'll move the rear axle rearwards and rework the spring more like standard configuration to get more spring travel while keeping the same stance.