Crankshaft assembly balancing

I've asked the engineering company who are grinding my crankshaft to also balance it with the pully, flwheel and clutch cover fitted, eg as an entire assembly.
They'll send it out to a balancer company at a cost of £120+vat which is reasonable enough i suppose,

Without knowing any better I asked them to balance it to ISO grade G6.3, eg 6.3grams mm/kg
Is this reasonable for a crankshaft assembly?
Also were is the best place to remove material? (I would assume on flywheel rim to achieve maximum effect?)

My only experience of balancing is on large industrial gears which i also specced to G6.3

Anyone have any experience of this or is it total overkill and not worth bothering with??

Good balancing is a must really.
I never balance crank with damper or flywheel as crank best balanced on it's own (internal balance) & adjusted via the counter weights by drilling out material or adding heavier plugs as required. balance damper & flywheel & clutch cover separately. Done that way your crank is balanced close to the source of inbalance which far better plus changing flywheel or damper has no effect on the crank assembly as long as new ones balanced close to zero prior to fitting.
most modern computer controlled balancers can get close to true zero balance, main thing with cranks is weighing pistons, rod, bearings & doing the maths right & setting bob weights properly.
Lot of myths & varying schools of thought on balancing so opinions & technique will vary. A lot of shops may have balancing equipment but only a few will have staff that make very good results from it.

That reminds me. When i worked at Nissan the flywheel, clutch and pulleys were just fitted. This and your post shows that these were all pre-balanced, which kind of tells me that i only need to rebalance the crank as thats the only part thats changed.
I might call the balancer and request they only do the crank to keep things simpler (and maybe cheaper).
Cheers

Yes as said above the crank needs dynamic balance on its own ideally
You then balance other items separately which as mr b said gives you a good over all balanced assembly

The better the balance the less likely you are to get premature wear.
Good balancing is paramount on any high powered application especially if rev limit is being raised.