I had a go at making my own pure grape juice wine a couple of weeks
back. I have a reasonable amount of experience of making country
wines and homebrew brews but I have never done "proper grape" wine
before.

Not having too much reference material, I think I juiced the grapes
too early which lead to a low initial gravity of about 1035 (instead
of a more recommended 1085 - I increased this via the addition of
sugar) but also the acidity is quite high too. The juice has now
fermented out and I had an initial tasting - it is generally very
sharp and a little lacking in flavour.

I am basicaly wondering how to improve it. My thoughts on this are,

1) Add a 1/2 oz or so of precipitated chalk and see how much the
sharpness decreases. Depending how this goes I would continue until a
more acceptable level is reached. If I do this how long do I leave
the chalk in for? Do I rack off afterwards or leave to a certain
period?

2) Or instead of drinking this wine "straight" use it to blend with
other wines (perhaps still doing step 1 above too?)

Any thoughts on either of these or other ways to improve it? Much
appreciated!