Help with crossover capacitors

Thank you for a clear explanation!  Is there a reasonably priced cap that you recommend?  

By combining capacitors would you just solder them end on end?  Big one first?  I have a ton of soldering experience but I don't know the science very much.  And what don't you like about the Dayton stuff?  Have you done an A/B comparison?  Is that different?  I have well trained ears but I also don't need the most amazing system. I was given these speakers so I don't know how much difference it will actually make between the Dayton and something like the Clarity caps.  I'm not going to spend any more than $50 a speaker to re-cap them.

I appreciate everybody's perspective on this as I'm sure there are different approaches and I will have to sort through it and figure it out myself and allocate my budget accordingly.
Millercarbon, I can definitely get with the idea that there will be a difference in Radio Shack caps and other more expensive brands.  I will look for a medium priced brand.  I am re-capping these speakers because they are 50 years old and I would like a fun project to do and when I re-capped a 35 year old mixing console (Soundworkshop 1600) I immediately heard a significant difference.  So, I'm just having some fun. 

Bill/Grannyring- I was just looking at those resistors and it's definitely worth giving it a shot at replacing.  I will include those when I do the work.  I am currently looking at either Clarity CSA caps or Mundorf Evo oil caps.  Each one will cost me about $150 total to re-cap at the same values.  I think I've got the idea, I just have to go back and check the resistors on those speakers and make sure I get the correct ratings.  I appreciate everybody's comments and ideas.  It is very helpful and is making this all fun.

And another question:  The resistors are 30ohm 15watt and 15ohm 10watt.  Mills makes both of these in 12 watt versions.  Will this work?

I would prefer to not have anything hyped but realistically it's all going to be a proper upgrade.  I will check the sale.  I thought the CSA's were more expensive than that, but I will order them now if they aren't.

The 5.6uf caps are not available.  Could I just use 2x 3uf caps in parallel to replace the 6uf caps?  Then I just order all caps of the same size.

Just ordered it.  Thanks.

I get that, but does that actually deliver more wattage to the speaker? Or does it give headroom to the circuit?

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?  

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.

Thanks to everyone for the help on this project.  I re-capped the Altec's with some Clarity CSA's, replaced the resistors with Mills (and one Mundorf).  They sound so much better.  I did one and then compared the two and it wasn't even close.  I am now hooked on this hobby.  I have 5 new projects going on with speakers and receivers.  I spend most of my free time reading about all of this.  Is this what happened to all of you?