There are no LP alignments ideal for 7" records. Least bad would be Stevenson IEC.
If you wish to get the best from a 7" record, draw yourself a protractor with nulls at say 53mm and 73mm (which should accommodated singles with inner radius down to 50mm) and use that to align your cartridge. You will probably find it is impossible with an arm mounted for a normal LP unless you can elongate the slots on a standard headshell to reduce overhang, or have a sliding base like SME, or can rotate the armboard. The offset angle is much reduced also, so the ideal would be to adapt a headshell to enable twisting the cartridge sufficiently.
Even if you are way off with you template by a couple of millimetres it will still give you way better alignment than a standard set up, provided you align accurately, potentially under 0.1% for a standard 7".