Wiring Gurus, help needed with circuit breakers, relays, dist block

[Josh69]

My car has the OEM fuse block and I'm not planning on replacing it just yet. I don't want to draw any power through it due to safety concerns for the new stereo, Vintage Air or DSE wipers other than switched 12v for relays. I understand the fundamentals, but have some questions on the details.

Here is what I want to do for the A/C and wipers, tell me where I go wrong:

-Pull 12v constant power directly from either remote starter solenoid on firewall or firewall bulkhead for battery cable instead of trunk mounted battery (which is better/worse?)
-Run 8-10ga (?) from there to a distribution block. Do I have to run a circuit breaker before or after the dist block? I'm thinking before since I'm dropping down in wire size...correct?
-Run 10-12ga from dist block to the relays under the dash.
-Trigger the relays with the accy switched 12v on the fuse block

Vintage Air supplies a 30amp circuit breaker, is that one enough for both the A/C and wiper relays? They say it has to be mounted under the hood, why?

I guess I need to know the proper 'order' of things. I don't want to have the circuit breakers in the wrong place, or not enough, or too many, etc. Same goes for wire gauge, etc. I don't want too much of a spaghetti circus under the hood or dash either...I already have my remote starter solenoid and a Jeg's 2 lug distribution block on the firewall and am running out of space to look clean.

[XcYZ]

I have a distribution block under my dash. I think it's a great way to go and makes things much easier to troubleshoot down the road as you can kill power to different systems as needed.

I'm not wild about relays for power distribution - just one more thing to go wrong... be it a mechanical or SSR.

[Josh69]

I think I like that idea.

I think I should re-route my remote start solenoid from the firewall to the trunk next to the battery so only the alt wire will be hot and fused with a fusible link.

I'll mount a 2nd distribution block up under the dash that I will use for the A/C, wipers, and stereo. The 8ga wire from the battery/solenoid will be fused prior to the dist block. The A/C has a 30amp circuit breaker after the dist block and before the two included relays. The DSE wiper kit has an in-line 30a fuse. So I'm covered pretty well.

I'll still need a relay for the DSE kit to trigger it with my light duty 12v switched power.

I've read that the Vintage Air kits need to go direct to the battery. I don't know if running my wipers and stereo off the same dist block will have any negative affect. I guess the issue is electrical 'noise'. If it needs to go straight to the battery in the trunk, then I'll just use my existing dist block on the firewall to power the relay for the DSE wipers and stereo.

I wanted to avoid having a bunch of live wires going to the trunk.