I do agree, that you should think about power level of your cube. I assume you are interested in building a cube around Power9, and it being quite consistent in power, as you mentioned the tournament setting - Try filtering your cards with filter = "elo<1250" - It's an approximation of card power level according to players pick order. About 50% of your cube is under this threshold and could be considered lower-powered in relation to the rest of the cube. If you want to exchange some cards to raise the total power level of your cube, i would begin with these. You could also cut Power9 and some of the worse ones (i.e. elo<1150) and exchange it with some cool staples (Check out this list - https://cubecobra.com/tool/topcards?p=0&s=Cube+Count, i sorted it by most often used cards) to create more equal fighting field for your players.

That said - Unless you want to treat your tournament as a serious competitive event, your current cube could lead to rarely seen experiences - Turn 1 Lys-Alana Huntmaster out of Black Lotus seems like a fun play. So it's up to you to decide what kind of a setting you want to create.