Looks like you're progressing quite nicely
Take it from me, I'm currently 86 (around 70k till 87) slayer, and I wear a black mask for every single task except Nechryael, as they require nose pegs. It
definitely is worth it's weight in..Uhm...Dragon Bars? It is quite priceless, that's my point. The extra offensive bonuses allow you to finish tasks faster, as well as being able to train your combat stats faster.
Basically, sell the D-Med, and buy a black mask. They're 350-450k, the lowest being quite late at night in a busy world, which is quite reasonable.
At any rate, Congrats to what you've done so far, and keep going till you get your goal
