Hi everyone, my first post here after much reading.
I'm a novice woodwork dabbler and have (foolishly??) embarked on making a new jarrah kitchen benchtop. It's U shaped, with usual stovetop and sink in it. So far I have glued my laminated sections together (weather resistant PVA and biscuits), and decided on butt joints where they meet. For this am thinking of biscuits with no glue and some sealant. My boards are only 19mm thick, so on the visible edges I have used some 2x4 roof timbers, recessed to look "L" shaped in cross section (wanted to make life hard for myself). The existing bench is laminex on 30mm thick chipboard, and is in good nick, so I was going to lay my new top onto it and secure it down, loosely as per everbody's suggestions. The thick edges of the 2x4 are to hang down and hide the chipboard. I'll make sure there's a gap so they don't get pulled off. My glueing wasn't perfect, of course, and I've got a few thin gaps in the laminate, less than 1mm wide.
I want to oil the benchtop (and underside, as per suggestions), and plan to use organoil hard burnishing oil, I think.
I glued up one section with epoxy (west system) but it stained the wood really dark, so even once sanded back and oiled the join looked darker. so then I just went for PVA.

My questions are:
1. How to seal up the gaps in my laminates. I"ve got some "Jarrah" coloured water based filler, but it's lighter coloured, esp when oiled . Could put epoxy in but scared of it blackening too much. I guess the advantage of epoxy would be some bond strength in an already compromised join. Maybe just stain the wood filler darker? so any suggestions welcome
2. What sort of product to seal the butt joints? It needs to be flexible, I presume. should I be glueing them?
3. Even if I seal the gaps well, I'm scared of some moisture getting under the top. So, should I leave the laminex on the chipboard, and thus seal the chipboard from above, or remove it and maybe give any moisture that comes down somewhere to go?
4. I was going to leave the existing tile splashback in place, and have the new top butt loosely up against it, and bolt the top down at the back and let it expand forward. Is this a recipe for disaster? What's a good product to seal oiled wood onto tile?
5. Anybody got a better idea than the organoil for an oil finish?

many thanks......Tommytank