You have everything in mind already that is great, with your rev rate I wouldn't rule out the Lx16 even though the ball is strong you will be surprised on how much it stores the energy and the move it makes is not extremely sharp however when it is coming out of the pattern I have yet to see the ball stop rolling from the highest rev player to the lower rev player.  I will agree with the 706c/a that you have listed that ball is not weak at all when you drill it strong, moving way in (as long as the lanes allow for that) will be a great choice.  On the down side you don't want a ball that you are only going to be able to use when it is time to get it because moving left it maybe to strong from the friction and moving in to early maybe too much oil in the middle.  300a that is always a great choice for the burn and or lighter oil.  300c I am not sure because, this ball can be strong a little stronger then you want, surface adjustments can be made I really think you will be able to use the 505c2 longer and get a better read with the layout you are thinking of going with.  These are all just assumptions without seeing you roll the ball and the type of patterns you will be bowling on.  I really think you have a solid foundation with what you have posted.  If you are able to get two bowling balls I would say 505c2 (try it box finish and then play around with as many surface changes as possible this ball takes them well)  And 300a this is going to give you medium and light conditions with your Berserk being the medium heavy and or heavy oil ball.  Once you see the reactions and compare the bowling balls I think this is the order you can go in.  Lx16, 706c/a, Mx10, 714c, 503a, 300c, Hx05 (this is from the top down like volume of oil from greatest to least) I hope this is can help you and not confuse you.

The cover on the Hx05 will get down the lane a little further then the 505c2, I did notice with the Hx05 and 505c2 (at box finish) the ball is going to pick up once it hits the friction.  However the 505c2 is going to keep going were the Hx05 is a little tame (depending on the layout and what you are bowling on).  I then wet sanded the 505c2 to 800 and this a different ball all the way around you will see a smoother yet stronger reaction its almost like this ball forgets that it is a pearl.  With the Hx05 I wet sanded it 500, 800, 1000, 2000, doing that I am about to move right when other people are chasing it farther left.  Doing this with the 505c2 it just picked up to soon, never be afraid to play with the surface on any ball.  I am able to do this with my rev rate being around 400-425, one thing you don’t want is to get a ball and find out it is not enough I rather a ball be to much then not enough (just my opinion) the 505c2 would be your ball to find out where you want to go from there either up or down more surface or less surface polish or sheen/haze.  In short the ball will get back from playing inside lines however depends on the layout, lane condition, how early or late in the day/night, speed and rev rate.  The Mx10 should give you more range for sure that ball is overall stronger then both the Hx05 and 505c2.  The Mx10 takes surface adjustments well also.  No problem please ask your questions I am glad I can help.