larger tyre up front on Mercury Mk3

[strictnaturist]

Hi folks
I'm heading over to Canada (from Scotland) this summer, to ride south for around 1000miles to Jackson, Wyoming on the Great Divide route with my son. Camping all the way. I'll be on my 6 year old  Mercury Mk3. My son on my old Sherpa.
A few adjustments to my Mercury for the ride will be dropping the gears from a 43 x 19 set up, to 39 x 19 and switching from slick 2.00 tyres to the largest gravel tyre I can fit. Guidance for largest tyres on the Mercury are 54 mm. The front fork looks like it has clearance for a larger tyre.
Can I ask? If it fits, Is it worth having a larger tyre up front? The route is predominantly tracks/ off road.
As an over 60, I have only ever used inner tubes. Is it worth switching to tubeless at this late stage? Or stick to what I know?
Any recommendations for tyres?
Thanks, as ever, for your comments and all round knowledge.
Eddie

[PH]

I'm assuming from those numbers that it's 650B?  I think it would need to be pretty extreme before you noticed any benefit going over 54mm, that's already a lot of air, more than in the Sherpa. My Nomad on 650B 50mm tyres offers a very plush ride over just about anything I'd tackle. I'd be concentrating on the right tyre for the tour, rather than the width.  I know nothing of tubeless, I am curious to try, but for me it'd mean changing rims which I'm in no hurry to do.
Have a great trip.

[JohnR]

I can't think of a good reason for putting a bigger tyre on the front than on the back. In fact, I've done the opposite and put a slightly smaller tyre on the front on the basis that it carries less load than the rear tyre.

I was almost 70 when I first encountered tubeless bike tyres and am now a convert. A key requirement for a good tubeless experience is tubeless-ready rims. A good tyre-rim combination can be inflated with a simple pump. A poor combination results in much cursing and the need for a pressure tank. While tubeless tyres handle small punctures well, the ability to prevent a flat caused by a bigger cut is less certain and depends on the cut size and sealant. I've had one ride-stopping cut in ~20k miles which was caused by a flint shard. Attempts to plug the hole were unsuccessful so tyre boot and inner tube were needed.

[Andyb1]

Think of motorbikes John, most have bigger front wheels.   The same thing is happening with MTBs.  The term mullet applies.
I usually fit a larger section front tyre run softer than the rear to give some ‘suspension’ when hitting bumps.  My logic is that the front wheel is pushed down onto bumps while the rear is more likely to get pulled over them.
Also if hitting soft sand, a wider front tyre should be more stable.