First, I must say I'm favorably impressed that such deep thought has been involved on a rebuild and that you are "detail oriented". Nice pics and detail points, too!
Here are my comments.
Seriously consider retiring the depicted caliper. The seal grove still has rather large and abundant corrosion pits, not conducive to sealing well or allowing the seal the operate well as a piston retraction "spring". I would only reuse such a caliper body after the apocalypse when a replacement could not be obtained. To get that surface flat and smooth again, would make the dimensions questionable for the standard square section seal. So, unless a special dimension seal is employed, I think that caliper body is doomed. imo
My question is, where does the silicone grease go and where does the "caliper assembly grease" go.
Referring to your labeled pictures, A2,B1, B2, B3, C1, C2, C3, and D1 but only on the side outside the seal interface. I.e. NOT A1 or A1.5.
The rule is that the silicone is used only as a water barrier to deny water contact to bare exposed metal. If air and water can get to exposed metal, it will corrode. The silicone grease is not used because of it's lubrication qualities. But, rather because it will not alter its material phase with heat and will not combine with water or other atmospheric contaminants, which can attack and convert the metals used with the caliper. In this design, the silicone lube is used in lieu of paint to protect the metal.
F2 and F1 should have a
thin coating on any metal surface that does not have a paint barrier.
any silicone based grease with heat resistance up to 200+ would due ?
No. Beware of package labeling, and salesmen eager to sell you something at profit. Advertisements of heat resistance can easily refer to its lubrication ability rather that it's phase state stability. "Contains silicone" is not the same a being pure silicone.
A grease or gel may only retain its physical state within a narrow temperature band. Get it too cold and it may solidify, get it too hot and it may liquify. I've yet to find a petroleum based product that does not fail to maintain phase state within the required temperature extremes. Worse, most of the petroleum products I've encountered, can't maintain 100% phase state even at room temperature, meaning they separate from the blended binders that make it a grease, rather than liquid oil, and then bleed or crawl along the surface away from the application point. For this particular caliper design, this means the friction pad and rotor interface can become fouled with lube. Even if the grease is labeled to remain an excellent lubricant to 500 degrees, it is not a comfort to me if applied to the very friction surface I need to stop the bike.
And any special do's and dont's regarding the "caliper assembly grease" ?
Assuming you mean "Brake assembly lube". It goes in the groove (A1.5) and on the seal. It is totally allowable to get a little onto A1 and the brake fluid end of D1, as it will simply dissolve into the brake fluid when it is introduced. Some will also remain in the seal groove next to A2. Some may even get onto A2. That is OK, imo, as it is far enough away from the friction pads as there is little chance of contamination. And, the assembly lube also has limited ability to keep water and air away from exposed metal contact (which keeps the seal grove from corroding).
Those are my recommendations.
But, I'm sure you'll get other responses, testimonials to the effect of "I used product XYZ and it works fine."
If you are determined to use substitute materials, make sure you do your own product testing for this specific application rather than simply rely on broad and/or nebulous package labeling.
I've tested some that failed requirements for this application. (And some that didn't even meet package labeling statements.)
Hope this helps,
