I am changing the fusebox this weekend due to a melted #16 & #1 with a really nice used one from a wrecker. Is there anything I can do to 'beef up ' the contacts for the fuses, tin them with solder, bend them tighter, replace with new bits ( the dealer is of no assistance with parts ) or just go ahead and hope for the best.

I replaced my fuse box with one from a junker.

here's a hint: take an old fuse and snip it in half, then use it to test
every socket connection. if it goes in loose, then you need to remove and tighten the crimp lug.

hint 2- constant insertion wears down the legs of fuses. maybe new ones
are better than the old. I have just got a harbor freight infrared
non contact thermometer that should show up lossy fuse contacts needing service.
(But I haven't tried it yet) If the contact gets loose then it will become a resistor and generate heat. PLUS how can they do 30 amps with those cheesy contacts? I can't figure that out!

Hint 3-Use dielectric silicone on the contacts

Let us pray, Bill :-)