Fuse 23 under hood keeps blowing?

Here's a trick to get you started. Plug a pair of universal crimp-style terminals into the fuse socket. Attach a clip lead / jumper wire to each one, then the other ends to a 12 volt light bulb. I use a 194 "peanut" bulb or a common 3157 brake light bulb because they're easy to connect to. You can find a pack of about ten jumper leads at Harbor Freight Tools for less than five dollars.

With this setup, the bulb will be full brightness when the circuit is turned on and the short is present. The bulb will get hot, so be careful what it is laying against or on. When you do something to make the short go away, the bulb will go out or it will become dim if the circuit is trying to work.

One very common problem I've run into with custom wiring is the use of electrical tape, and wires that are just twisted together. Instead, splices should be soldered, then sealed with heat-shrink tubing. Electrical tape unravels on a hot day making a gooey mess. Under the dash, you don't need the more expensive heat shrink tubing with hot-melt glue inside. That's for keeping moisture out and is more suited for under the hood.

Once you solve the short, the radio will try to work, but the test bulb will be using up part of the 12 volts, leaving much less than 12 volts to run the radio. Reinstall the proper fuse and the radio will work properly.

For the next couple of months you might consider carrying a battery jumper pack with you. Many Honda models have an unusual circuit that "polls" every electrical component and computer on the car, and calculates how much current the generator must develop. That list includes the original radio. Aftermarket radios don't get included in that calculation. That could leave you with a battery too run down to crank the engine after a few weeks or months. If you don't run into that problem after a few months, you should be good to go. If that does occur, charge the battery at the charger's slowest rate overnight every few weeks.