I don't often post but spend a fair bit of time working with cutting lists and angles so might be able to help.
As Mike says, with angled cabinets the angle of the lower side can be very awkward to cut. With a 35degree angled cabinet the lower side of the top panel would need to be cut at 55degrees if using the 'top between the sides' construction method. That's a tricky angle to cut. One alternative is to bisect the angle for the lower side. Similar to mitring but with an angle that reflects the angle of the cabinet top.
For that example 35degree angled cabinet, the cabinet top and left side would need to be cut at 27.5degrees, an angle much easier to cut. Because they are cut with the same angle they will meet end grain to end grain perfectly giving a neat finish.
This joint can be reinforced with a dowel/screw/biscuit/domino - anything that creates a joint perpendicular to the end grain.
For the higher side of the cabinet bisecting doesn't work but the angle is easier to cut : 35degrees. One technique to beef up this joint is to attach a fixing block as shown in attached diagram.
To work out the dimensions and angles for the panels you can either do it by calculation or do a full size drawing on a sheet of 8 by 4. To accurately bisect the angle for the lower side use a couple of scraps and determine the angle by making trial cuts on the saw and then offering up the pieces to the drawing. Start at, say 15degrees and increase the angle until the pieces match the cabinet angle on the drawing when butted up together.
My jobs are done on automated machinery so I pre-calculate the sizes/angles but one of the advantages to using the full size drawing method is that you can quickly see whether the end result is right or not!
HTH
Andrew
