So this is a start.  I found the TSQL formula I was looking for.  The two formulas below will give you the beginning and ending of DST.  So then you will need to do a compare to the current date to determine whether to subtract two or three hours.

datetimevar StartOfMarch := dateadd('m',2, dateadd('yyyy', year(currentdate)-1900, date(1900,01,01)));
datetimevar DstStart := dateadd('h', 2, dateadd('d', ((15- datepart('w', StartOfMarch)) mod 7) + 7 , StartOfMarch));
dstStart

datetimevar StartOfNovember := dateadd('m',10,dateadd('yyyy',0,currentdate-1900));
datetimevar DstEnd := dateadd('h', 2, dateadd('d', ((8- datepart('w', StartOfNovember)) mod 7) , StartOfNovember)) ;
DstEnd