Performance gains

Wanted to ask what do you think will come up.
I have an idea to put 1.3 cams on my 1.0 and skim the head 1.5-2mm.
And are the 1.0 and 1.3 heads differ only in the cams or are they different in other things(flow,combustion camber of the head and etc.)
I know that there are proven gains only with the cams but will
the head skim help two?
And will 2mm skim be too much?

2mm is a lot for a 1.0 ! and it makes the lower chain pretty loose.
1 or 1.5mm is well worth it tho
and same heads, just different cams

Thanks for the quick reply Frank,i was crossing fingers that you see the post :) .
Will the loose bottom chain advance the cams too much?
Will there be a noticeable difference with 1.5mm skim or just the cams
will take the major effect.
Because the work with dismounting and working on the head is much harder.And with the 1.5mm off the head what can be the expected CR.

the chain slack will depend on the milage really mate, a new chain will have some adjustment left even with 2mm, but the tensioner will be maxed out on a 100k mile chain
1.5mm should be about 11:1 on a 1.0 i guess
and i have my 2mm skimmed and weldfilled head fitted to my current CG10 + t, running 10 psi at the mo (with 2 gaskets tho, so 1mm skim really)
the cams will be retarded from the skim, so advancing required
you can just about see the wellfill here