The 75g does not have enough material to remove any, its basicly a tapered sleeve, been there tried that. About all you can do is drill out the end, that only removed about 10g.
One thing you can do, take 35g worth of splitshot sinkers-put them in a new (clean) field point or blunt-heat it with torch till the lead melts-when its molten, tap it lightly on the bench to settle the lead-let cool for a minute or so then smack it on the bench and a nice tapered weight will fall out. Put that in your BH ferral, you will have to shorten the taper on the shaft a little but you should still have enough.
I've bumped 125's up close to 160 this way.
Eric