I have always used the converted clothes peg for Seep alignment.
Before fixing the Seep and with the point temporarily in its final position I drill 2 x 1mm dia holes at the exact middle outer edge of the points moving tie bar (Stretcher bar) each hole marks the position of the points tie bar centre line underneath. A third hole is drilled with the point blades held central through the tie bars drive pin hole. Remove point draw a line linking the two outer holes which should also pass through the drive pin marked hole hole, then from the top using the central drive pin marked hole and pencil line drill two 4mm dia holes side by side each side of the central hole. Elongate the two 4mm holes into a slot and ensure any wood burs are smoothed away both on top and underneath the baseboard. Refit point into its final position ensuring its positioned exactly where the 2 x 1mm holes were drilled on the outer tie bar edges. Secure the point blades mid position. I use on Peco OO points a U shaped piece of 16/0.2mm equipment wire between the open blades as this is a reasonable tight fit and doesn't over strain the blades. It can be held in place with a strip of masking tape if wished.
On the underside of the baseboard locate the two x 1mm holes and using a straight edge and pencil draw a line connecting the two 1mm holes and extend that line out beyond each hole by about 20mm on each side. The line should also pass through the slots middle too. Fit wooden clothes peg to Seep which holds the Seep motors drive pin central. Place Seep into position and engage the drive pin into the points tie bar hole above. Aline the Seeps circuit board middle with the pencil line.
Mark the two fixing places and drill fine pilot holes where marked and then screw the Seep in place ensuring the point blades are still held central and Seep circuit board is still central on the pencil line.
Remove peg and wire holding blades central.
By hand move the underside of the drive pin left and right and the point above should follow. Cut off surplus drive pin and job is done. BTW I use an 8" inch pair of cheap wire cutters to cut drive pins and I never use an electric mini drill with slitting disc, as the heat generated can cause the plastic of the tie bar to melt!
The above reads as though its a lot of work, but in fact its relatively simple and virtually fool proof!
How to make a Seep holding peg is here... http://www.modelrailforum.com/forums/index.php?automodule=blog&blogid=53&showentry=998
Broken? It was working correctly when I left it.