Partial ROM Pull-ups/Chin-ups?

Would it be a good idea to do partial ROM pullups/chinups with heavy weight?

I can do BW+70 full ROM but feel i could probably do BW+120 or more for 3/4 of the way.

I am very week at the top of the movement, and am not sure if its due to weak biceps, or just bad levers at these small angles.

I was thinking of going much heavier, and only going about 3/4 of the way up, and then doing weighted static holds at the top positon, and maybe even weighted isometrics in that position.

What do you guys think?

Do whatever you believe helps you get stronger. There was a huge discussion/flamewar about this not too long ago.

Just don’t go around talking about how you can do X pull-ups/chins or BW+Y for a max rep if your chin isn’t over the bar and you don’t start from a dead hang.