I always had my Naks (5 in total) internally tweaked for Maxell UDXL II by a tech and that seemed to make the most difference. Sound floor dropped, dynamics went up as I could run very hot and avoid distortion and the phasing just seemed to be dead on. No Dolby as that seemed to roll off the high end and do funny things with phase. I will tolerate a bit of tape hiss for a markedly truer reproduction.
do you need to tweak a tape deck???
...after experimenting with Onkyo 2060 tape deck I've discovered that it records better standing on the vibrapods. Moreover it improved when I've leveled it properly. Is it just I'm going nuts or someone can also state the same?