Sounds too large at 4 degs, if we're talking about high-subsonic cruise.
I'd expect a cruise alpha in the range of 0-2 deg body, with a wing setting angle (incidence) of no more than 2 deg more. That means the wing alpha is going to be between 2 and 4 deg. Assuming, as ever, a downwash ratio of 0.5, that implies that a tailplane AoA of zero will be achieved with a tail incidence of about 0-1 deg:
For a body AoA of A and a wing incidence of W, the tail AoA as a function of Tail incidence will be:
tail AoA=A+T-(A+W)*0.5 (1)
So for a minimum tail AoA=0, we get:
T=(A+W)*0.5 - A = (W-A)*0.5
Therefore for A=0, W=2: T=1
for A=2, W=2 : T=0)
If the expression (1) is rewritten in terms of longitudinal dihedral D, where D=W-T, then we get:
tail AoA=A+ (W-D)-(A+W)*0.5
or
tail AoA = (A+W)*0.5 - D
so for a min drag tail AoA of 0:
D=(A+W)*0.5
Which for typical values, again, of A and W in the 0-2 deg range each, gives a D also in the 0-2 deg range