Thanks for the clarification. There aren't different types of connectors. Instead of specifying a shape type, modify the dgm:param list. Here's a starting example:
<dgm:alg type="conn">
<dgm:param type="connRout" val="curve"/>
<dgm:param type="begPts" val="radial"/>
<dgm:param type="endPts" val="radial"/>
<dgm:param type="endSty" val="noArr"/>
</dgm:alg>
Here the connector is modified to 1/4pt width with to make a thin line:
<dgm:alg type="conn">
<dgm:param type="dim" val="1D"/>
<dgm:param type="connRout" val="curve"/>
<dgm:param type="begPts" val="radial"/>
<dgm:param type="endPts" val="radial"/>
<dgm:param type="endSty" val="noArr"/>
</dgm:alg>
Here the connector will acquire an arrow at the end:
<dgm:alg type="conn">
<dgm:param type="connRout" val="curve"/>
<dgm:param type="begPts" val="radial"/>
<dgm:param type="endPts" val="radial"/>
<dgm:param type="endSty" val="arr"/>
</dgm:alg>