Just had a few games...

I premiumized for a day to test it.

In a T7, non-master...

Without premium or aide, win, 150k attack, 4.5k exp, 2.7k credits
With premium and aide, win, 1 sub downed, 80k attack, 10k exp, 6k credits

That means exactly 3k without event and premium for that 2nd game:

( 3000 * 0.5 ) + ( 3000 * 0.5 ) + 3000 = 1500 + 1500 + 3000

Mastered ship you would add another 1500 credits, bringing the grand total to 7500 credits.

Well... Assuming we'll boost exp rewards, credits reward would probably need to be toned down a bit. 1.5-2k before premium and event perhaps? Iows, around a 33% less before all the non-multiplicative bonuses for premium and event are taken into account, if they are non-multiplicative.

That way the same game would've netted 4k with premium and event. 3k with premium OR master only. 4k with premium and master without event. 5k with premium, master and event.

What do you captains think?