Clomid changes mood, sometimes causes acne.
Nolvadex does not do either for me, and in that large post floating somewhere comparing clomid and nolvadex, nolva came out on top.
Wait 2-3 week until after your last shot of the deca300 to begin your clomid/nolva PCT. For details read the sticky on the top of the posts. It contains a lot of good detailed information.
"Nolvadex, used for 10 days at a dosage of 20mg daily, increased serum testosterone levels to 142% of baseline, which was on par with the effect of 150mg of Clomid daily for the same duration"
Taking both does not mean clomid is adding anything more than replacing the clomid with more nolvadex.
Nolvadex also increases the pituitary's sensitivity to GnRH, while clomid does the opposite. GnRH is responsible for LH release, thus increasing the pituitary's sensitivity to GnRH will further increase LH production and thus increase testosterone.