There are no good options, but some are better than others.
First: Do No Harm. Well, actually first make sure you use as little energy as possible. The “low hanging fruit” in the energy budget is reduce usage. For example; a typical incandescent anchor light uses 2.5 amps. For 10 hours a day, that would be 25 amp-hours per day (Ah/d). An LED anchor light might use 0.090 amps, or 0.9 Ah/d.
To estimate the energy a solar panel will make, take the wattage and divide by 3 to get the Ah/d. So, an incandescent anchor light will need 75 watts of solar panels. An LED anchor light will need 3 watts. Solar panels make about 15 watts per square foot. You don’t have enough area for all the panels you need if you are on an inefficient monohull.
The best place for solar is where there is no shading. A little shading can make a big difference. A rigging wire or line shadow not so much, but a pelican poop can reduce output by 50% or more. On a boat, high and aft is usually the best. No arch? Maybe what I call a table top: Basically four legs and a platform, using one inch stainless tube and bimini top hardware.