The spider locks are undoubtedly the best holder on the market. The base is almost flush to the deck and very strong. Infinitely adjustable. The seats have gained a real following with most of the guys here in the Midsouth region. On the Dub- L- Seat. I know the guy who invented it then sold it. The guy who has it now has made great improvements in it. He also came up with a mount for your Ranger that locks in place. I have fished from 3 different ones and it is the best of the bunch. He is so high on the safety aspect that he has a 1 mil insurance to cover you if something fails. And he is very customer oriented. Have seen him take back old seat setups and either repair or replace them for free. Yes they are pricy but safety,adjustability and customer service come with a price. And no I am not affiliated with him in any way.
Proud Member of Team Geezer
Charlie Weaver USN/ENC 1965-1979