A better scythe should be at the top of your Priority list. Reckoning in particular, is easy to get and quite powerful, even if you're not looking to get the fabled 5 hit setup (Which requires significant sacrifices or the Goading belt from TIII Abyssean NM Lacovie)
Brutal earring is the second most important upgrade you can make after the scythe. You're either a liar, or really do have a Velocious belt, so the thought that you do not have a Brutal earring already is more confusing than a room full of trensgender bisexuals.
Snow Gorget will get you slightly more power on Guillotine with roughly the same Accuracy boost. If you're capped on Accuracy, Justice Torque will (Slightly) outperform a Snow Gorget on Guillotine, only because fTP bonus is only applied to the first strike.
Fire Bomblet is probably the weakest upgrade you can make in that set. If you are capping accuracy, the Bomb Core
will outperform the Fire Bomblet, without any questions, and if someone says otherwise, they have severe brain damage. Still, it's an item you should look into getting, since that setup suggests you haven't invested the merits into DRK to make it a capped-accuracy on all targets (With pizza).
People have already said it, but get an Attack cape for Guillotine. Smily Mantle is fine for Greatsword or Spiral Hell, but Guilltoine, being a Four-hit attack needs to calculate attack scores and generate the damage four times, combined with the fact it doesn't recieve a pDIF(Attack) bonus like the aforementioned Spiral Fail and Spinning Slash.
For your TP set, Rajas and Blitz are a better combination than Kusha/Luva. If you are lacking Rajas because of another ring choice, Blitz and Toreador's(Any acc ring) will be an improvement, Assuming you are using Pizza like any good DD nowadays.
Finally, if you pursue the Reckoning or get a Rajas, you can switch your Grip to a Sword Strap, and still maintain a 6hit /SAM with a 528 Scythe. If you have the reckoning with StoreTP augment, you obviously wouldn't need the Rajas to use the Sword Strap.