Working on the Truck Bed

[ACK]

I'm working on the truck bed and making good progress. The PO screwed Trex on top of the bed wood, surprisingly, the wood underneath isn't in bad shape, other than some splitting. A rear bed sill and front bed panel are on order from FixMyRust.com, haven't used them before, but the prices are good and shipping is free. And while the bed is off, going to clean up the frame and paint it.

Not having taken a bed apart before, I'm looking for wisdom from those that have. It's a short bed fleetside and a daily driver:

• Are the wheel tubs bolted to the inside bed panels? There's so much crud in there, I can't tell.
• The bed mounting pads are non-existent. The replacement set contains 8, but there's only 6 mounting points to the frame, where do the other 2 belong?
• Does the rear bed sill have 2 points where it's welded to the bed? If yes, should I grind the old sill off and does the new sill need to be welded at the same spots or is it not necessary?
• If the bed wood is worth keeping, should the splits be glued closed?
• The bed wood is staying old school, linseed oil and lamp black. What's the ration of oil to black?
• The new bed strips are zinc, how about spraying them with bed liner rather than paint?

I've checked the FAQ, any additional advice is welcomed. I want to keep the dummy tax low on this project.