I agree with tuning to suit. Go for the C in place of the B.
A 6 can get a lot of work load in a metal band, particularly if you like the classical scales, and riffs.
Have the guitarist give you some scales to work on.
These will help you feel comfy with the 6 string.
I'm a bit odd myself, I like 4s and 6's, but do not really care for the 5's. I try to work with plenty of genres and use the frets board all over. Having said that, you can still kick serious butt with 2 strings and a few simple notes that are well placed and dead on.
But, you should be able to do that just as well with a 6, and have plenty of options to toy around with. Metal is as good as you want it to be, likewise, you can infuse the metal also with jazz, extended ranges, funky stankiness etc.
Most metal bands are receptive to funkiness, well, except for Metallica, bunch of dumb $ grubbing fools, glad Les did not join them.
Better off musically (not $ wise).
Tom