I have made all Pokeblocks in Lilycove. All were level 61 feel 34. So, you can only feed 8 Pokeblocks to a Pokemon.

Here is small table what contest stat rises using which Pokeblock frow a berry:

GanlonSalacPetayaApicotLiechi
Cool01049061
Beauty61010490
Cute06101048
Smart4906100
Tough10490610

I have fed five Pokeblocks to my Metagross form each of the above berries. And then three Pokeblocks from three of the above berries. I don't remember which berries I used exactly for this three.
Using the above table you can calculate the contest stat value your Pokemon will get. Feeding five Pokeblocks one from each berry you will get a value of about 120 for each contest stat. Then you can decide which stat is more important to you and feed the other three Pokeblock.

There is one possibility to max out all stat contests. But it is not very easy. The problem is you need two e-Reader berries. One of them is only available in japan and works only with the japanese version of Ruby/Sapphire.
With some friends I tried this on the Pokemon Day in Munich. It really works!

Here is the explanation what you have to do copied from another forum:

This will require four players with access to Berry Blending, along with
two of the four players using e-Reader Berries (specifically, Nutpea and
Kuo Berries). So this isn't a really viable option for most people. It
also requires Liechi Berries, so that's going to be a pain:

Mix:
Kuo + Nutpea + Liechi + Qualot.
Kuo + Nutpea + Ganlon + Hondew.
Kuo + Nutpea + Salac + Grepa.
Kuo + Nutpea + Petaya + Pomeg.
Kuo + Nutpea + Apicot + Kelpsy.
Do this again.

You should now have ten Pokeblocks.
Two Spicy and Sweet, about Level 60. Feel 23.
Two Dry and Bitter, about Level 60. Feel 23.
Two Sweet and Sour, about Level 60. Feel 23.
Two Bitter and Spicy, about Level 60. Feel 23.
Two Sour and Dry, about Level 60. Feel 23.

These Pokeblocks should raise both Conditions by sixty points, if Pokeblock-making works the way I think it does.

When a Pokemon eats all of these Pokeblocks, their Feel will rise up to
230, and each of their Conditions will raise about 60 points four times
(as you can see in the above list, each flavor appears twice, and thus
has two Pokeblocks for it each time) or about 240 points.

You only get a few more Pokeblocks until your Pokemon is full, so you
can make one to raise one contest stat by about 20 points (that is, max
it out), and then make one to raise all the other contest stats by about
10 points.

So first mix:
Kuo + Nutpea + Bluk + Qualot.

You should have a Level 20-ish Sweet Pokeblock with 8 Feel.

Now mix:

Durin + Pinap + Razz + Aspear.

You should get a Pokeblock that is Spicy, Dry, Bitter, and Sour, and
Level 10. Feel 29, but this isn't important, since it should bring you
past 255 anyway..

Final results:

Cool: ~250
Beauty: ~250
Cute: 255
Smart: ~250
Tough: ~250
Feel: 255

If you wanted to, you could mix some Kuo + Nutpea by themselves, for
Black Pokeblocks, since their Feel will be 3 (but their Level will be 2
or 1, so it's only a teeny tiny boost) and so you can eat five of them
(as that would bring you to 254 Feel, letting you eat the final
Pokeblock). Alternately, you could feed an additional Level 10 Feel 8
Pokeblock before this, but you only get the one (you have 15 Feel to
work with, at this point, so an 8-point one would leave you with 7 Feel,
so while you could use another two Black Pokeblocks, you can't use
another Feel 8 one), but it could still be useful if you want to
guarantee 255 in another stat.

However, since I expect you to be able to get Level 62 Pokeblocks in the
first part (this is a guess, but I'm not sure yet how it all works as
far as spinning goes), you should have 255 in all Contest stats at the
end anyway.

This assumes a neutral nature, since otherwise one contest is 10% better
and one is 10% less, making it much more difficult (although you could
probably fix that by simply making three of super-Pokeblock and one of
another, or somesuch...).