Six years ago I put LED bulbs into the dome lights of my H23,5, and my friend's H260. They are wedge base, not festoon. Here is what I ordered from marinebeam.com at the time:
Name Code Qty Each Options
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Wedge Base 10-LED Side WG-SP-12X-WW 10 14.00 Output Color = Warm White
Mount Replacement
X-Beam
Subtotal 140.00
Coupon discount (ranger) -14.00
Subtotal 126.00
Shipping 19.95
Tax 0.00
Total 145.95
I replaced all my nav lights too with LED. I believe all my lights are Aqua Signal Series 25, and I believe they are all festoon. I haven't found the order yet, but I'll post more info if I can find it.