Tubes

I have recently come upon a tube amp a yaqin mc 13-s. I have been reading up a bit on tubes and different things to get better sound. I have asked some questions about speakers on here and received great feedback and its all very much appreciated, you guys who gave me your best input thank you. 

I paired my yaqin with a pro-ject tube box s2. Prior to purchasing the pro-ject preamp I came across a shiit lyr 2 and used it for a short period, unfortunately I'm not into headphones and it didn't pair well in my system the volume just want there because it's not really a preamp it's a headphone amp. Long story short it had ecc88 orange globe amperex tubes and that thing sounded smooooootthhh. 

So I have a few questions?
1. Should I change all the tubes in my main amp to matching tubes? It uses qty 4 (6ca7's or el34b's), qty 2 (12ax7's) and qty 2 (12au7's) for example if I were to use tungsol 12au7's should I use tungsol for the 12ax7's and 6ca7's or could I use gold lions for the 6ca7's? Does it really matter?

2. How big of a difference does it really make changing preamp tubes? like I said earlier the schiit really sounded great and I could only attribute it to those tubes but correct me if I'm wrong? I didn't have any other tubes to try.

Thoughts and opinions are all welcome and appreciated. Once again thank you all for the advice.