Lost x y edge when using rank=same

I'm trying to visualize doubly linked lists using GraphViz. An example:

digraph List {
    rankdir=LR;
    node [shape=record];
    0 [label="{<prev> | <length> 2 | <tone> 1 | <next>}"];
    1 [label="{<prev> | <length> 1 | <tone> A | <next>}"];
    0:<next>:c -> 1:n [arrowhead=vee, arrowtail=dot, dir=both, tailclip=false, arrowsize=1.2];
    1:<prev>:c -> 0:s [arrowhead=vee, arrowtail=dot, dir=both, tailclip=false, arrowsize=1.2];
}

The result is fine except for one thing; the height of the elements. With each consecutive element added the height decreases, I want all elements to be on the same height. But when I add

{rank=same; 0; 1;}

a GraphViz error occurs (Error: lost 1 0 edge). Now, the only fix I could find for this error is to replace the record shaped nodes with plaintext nodes and using HTML labels to create the record shape. I tried this, but it produces the same error.

The code using HTML labels:

digraph List {
    rankdir=LR;
    node [shape=plaintext];
    0 [label=<
    <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
        <TR>
            <TD PORT="prev">     </TD>
            <TD PORT="length">2</TD>
            <TD PORT="note">1</TD>
            <TD PORT="next">     </TD>
        </TR>
    </TABLE>>];
    1 [label=<
    <TABLE BORDER="0" CELLBORDER="1" CELLSPACING="0">
        <TR>
            <TD PORT="prev">     </TD>
            <TD PORT="length">1</TD>
            <TD PORT="note">A</TD>
            <TD PORT="next">     </TD>
        </TR>
    </TABLE>>];
    0:next:c -> 1:n [arrowhead=vee, arrowtail=dot, dir=both, tailclip=false, arrowsize=0.8];
    1:prev:c -> 0:s [arrowhead=vee, arrowtail=dot, dir=both, tailclip=false, arrowsize=0.8];
}

I would appreciate any suggestions on how to solve this issue.

A previous attempt looked like this:

digraph List { 
    rankdir=LR;
    node [shape=record];
    0 [label="{<prev> | <firstName> Wolfgang Amadeus | <lastName> Mozart | <instrument> Klavier | <next>}"];
    1 [label="{<prev> | <length> 1 | <tone> A | <next>}"];
    0:<next>:c -> 1:<prev> [arrowhead=vee, arrowtail=dot, dir=both, tailclip=false, arrowsize=0.8];
    1:<prev>:c -> 0 [arrowhead=vee, arrowtail=dot, dir=both, tailclip=false, arrowsize=0.8];
}

Here there is no clear distinction between the two arrows. Getting two distinct arrows between the nodes would also solve my problem.