sIFR 3 +li menu offsetTop position

I'm using sIFR 3 (beta revision 436). I have a menu 40px high. I have 9 links, 6 of which are one line and 3 are 2 lines. To arrange the single line links within the centre I have offsetTop by 11, example code of the sifr-config here:

sIFR.replace(herculanum, {
selector: '#menu ul li',
css: [
'.sIFR-root { background-color: #000000; text-align: center; letter-spacing: -0.35; display: inline-block;}',
'a { background-color: #000000; color: #FFFFFF; text-decoration: none;}',
'a:hover {background-color: #FFFFFF; color: #414141;}',
'a:active {colour: #000000;}',
],
offsetTop:11,
tuneHeight:5,
}
);  

I have tried using spans but I think I must be using them wrong.

sIFR.replace(herculanum, {
selector: '#menu ul li span',
css: [
'.sIFR-root { background-color: #000000; text-align: center; letter-spacing: -0.35; display: inline-block;}',
'a { background-color: #000000; color: 开发者_如何学Go#FFFFFF; text-decoration: none;}',
'a:hover {background-color: #FFFFFF; color: #414141;}',
'a:active {colour: #000000;}',
],
offsetTop:-11,
tuneHeight:5,
}
);  

I am really spun out about this please help.

use display:block on the spans?