might be an idea to approach Widnes about a swap -Russel for Joe Mellor?

That should encourage them to become marquee players themselves by developing their core attributes, skills and value to a team. If they cannot reach the standard they can have no complaints.

....if a player is on the lower spectrum of worth....to have a full cap and compliment or marquee ruling.....means you have a greater chance of winning big cup final bonuses.

Even at the upper level. Brown is apparently on less money at Warrington but he has the opportunity to dwarf the Widnes contact with the bonuses.

Bonuses count on the salary cap. Prize money doesn't and that is not very much these days.

Correct. On duckies point though - the "bigger" clubs will be able to provide more than just a salary. Accommodation, cars, nutrition (free meals) etc.

So you could earn less at Warrington due to it being a big pond, but still be substantially better off for it.

I assume that "benefits in kind" would count on the salary cap otherwise it would be too easy to circumvent.