You can simply use an angled miger gague on your TS, with a box joint
jig (long board screwed to the gague with a pin) to cut the slots in
your side pieces (stiles?)- with a dado head set to the thickness of
your louvers. Make sure the boards that you are slotting have
additional length to them, as it gets kinda hairy trying to cut the
last four or so slots without the extra length. Measure the length of
that slot (from longest to longest), plane your louvers to the
thickness of your slots & rip the edges of the louvers so the edges of
the louvers are angled to match the front of the frame. You could do
the same with a router table & a box joint jig i would imagine, though
Ihave not done it that way. Also, the RAS could be used with a dado
head & the RAS head turned to cut your appropriate angle. Make sure you
engineer a stop system so the slots are the same distance apart.
Remember, the larger the louvers (in width) and the greater the angle
of the louver the less slots you have to make. HTHs
Phil