Your Opinions Please

OK I'll try to hit the hi lights here, If I miss some thing , Just Ask.

Body Filler - Anything from Evercoat, good stuff, the differences between the different names of filler is the consistency AKA thin for shallow dents n thicker material for larger fills. I forget which one is thick n which is thinner. Rule of thumb is 3/8" Max filler Depth. See Below.

Solder- I used it in certain places, bought the "Kit" from Eastwood including the video. Not too hard to do, If you ever sodered wires or sweated 2 copper pipes together, You'll pick it right up. It's all about keeping the solder not to hot not or too cold. And it will out last filler by a long shot. A trick is to fill your larger dents/voids with soder and the skim coat with filler. More $$$ than filler but you'll never have to redo it.

Dents - Get em Banged out ,Suction cup, Welded Studs, What ever.... To with in 1/4" of flat, use Solder or filler, Depending on depth. Again Less filler is better. A run of the mill body tool kit... Hammers n dollies, Is good enough to get most jobs done.

Chemicals and mechanical or sandblasting - OK I'm assuming your asking Surface prep. Theres a lot of ways to get it done. Here's my 101. For the underside and engine/ trans/rear, a Pressure washer of any kind is Great for the inital removal of years of road grime. Undercoat comes off easy with easy off oven cleaner and a putty knife. Then I sandblasted the under side using a Harbor Freight Suction feed gun, It worked, but I'd use a pressure feed next time. (Either way, it's the worst of the worst jobs.) I then, after all clean coated everything with 2 part Epoxy Primer ( See local body supply shop.) Use White, unless you know your final color it can be tinted close, Which will save you a bit of paint in long run.
For the Outside of the car, I prefer non toxic paint stripper and again the putty knife, Followed by 60-80 Grit Sandpaper on a dual action Sander. Epoxy Prime and do body work over it and or reprime any bare areas.

Rust Converter - I use whats called OSPHO ..again auto body supply place great for tight areas. Converts the rust to iron. put rust encapsulator over it.

Rust dissolver?- see above

Rust sealers?- See above - Epoxy 2 Part primer

What size sandblasting machine? Any tips? -- Electric 5-7 HP 220v with like 80-150 gal tank, is Sufficent to do it all. I use /have a 13 HP Gas fired compressor w/30 gal tank. Having DRY air is the biggest Problem while sandblasting or painting. Spend $ On getting dry air to your paint gun.

What brand of paint? - I used House of Kolors, Basecoat/clearcoat system. There's several different types of paint. Basically I'd think basecoat/ clearcoat is most popular these days.

What about adding pearl or flakes? Pick your basic colors for the car, it can allways be "adjusted" for what you want it to look like and what you . You can spend $50 on this part or Several K$

What tools are a must have for sanding? -- Check Eastwood for Sanding Boards and the corresponding sandpaper. I used the 16" flat board seemed long enough. 80 Grit to start...2nd worse job..LOL, You also need Lots of Muscle and endurance when your hand sanding it. My Muscles hated me for WEEKS while doing this.
Too know if your surface is flat, Get what's called guide coat (Basically a quick drying thin primer) in a spray can. Spray it lightly Sand... Anything that stays black is a low spot. Sand and/ or fill more, SAND, Sand, Sand. If you want to see if it's straight, just pour some water over it n you'll see the reflection, it should look like a mirror.

Ok long enough, Just Ask!