Help with crossover capacitors


I am re-capping some Altec Lansing 890C Bolero speakers.  They have 6uf/50volt and 3uf/25 volt caps.  What will change if I use 5.6uf and 3.2 caps?  I can't find the exact 6uf and 3uf values.  Should I go a little bit higher on those values or lower?  Any suggestions?  I'm looking at Dayton, Mundorf or Jantzen caps but I'm open to suggestions.

dannybad
These speakers are rated at 50 watts at 8ohms.  I'm going to buy the Yamaha s-501 which is 85 watts per channel at 8 ohms.  I will turn them up and listen to them loud sometimes, but "loud" is a relative concept.  How exactly would I double up in parallel?  Would I just use 2 of the same resistor?  
Those are modest figures - I think you should be fine. I would not bother. But if you want to do so, the rule is twice the resistance for two resistors in parallel.
Great.  I think it will be fine as I really don't push them too much. Thanks for commenting.  Everyone on this thread has been so helpful.
And another question:  The resistors are 30ohm 15watt and 15ohm 10watt.  Mills makes both of these in 12 watt versions.  Will this work?
Two 15ohm 12watt resistor in series will give you a 30ohm 24watt.
I get that, but does that actually deliver more wattage to the speaker? Or does it give headroom to the circuit?