Concrete mixing and Patio slab cutting

[TheBloodguard]

I will probably rent a Concrete saw ( $70 for 24 rental and $45 for blade) to cut some
holes in my 3"-4" slab in order to have some deeper foundation support for some Patio beams.
I have quotes for $50 a hole for core cutting and $30 for normal concrete saw
cutting but I was thinking of doing it myself since it would save ~$150 over normal. The
core cutting would be ~$400 and look nicer but I'm not too concerned with the overcuts in the slab if I use a normal saw. I plan to get 8 holes cut

Anyone with experience on DIY slab cutting? Should I cough up the extra dough and
have someone do it or go for it? Not a huge amount of money but it would be nice to
save if possible.

I will also need to fill in the holes with cement after I dig out the foundation holes 1' deep by 1' wide. How about DIY cement mixing? Rent a mixer? I have not asked for quotes on having someone do this yet.

Any helpful advice appreciated. Thanks

 

[CPA]

Can't help you with the slab cutting, but the cement mixing, just use a wheelbarrow and a hoe. I assume you are putting in 4"x4" piers into the holes.

 

[TheBloodguard]

I plan to use 6 X 6 Piers, already have some installed at the end of the slab.
A friend did a small slab for a 4X8' shed and I noticed that the surface of that is very rough due to the surface crumbling (seems powdery or dusty). I was thinking maybe poor mixing might have been the problem which is why I thought a mixer might be better that hand mixing.