I improved my Honda Deaville by putting heavier fork oil and added pre-load on the fork springs by using 2mm this penny-washers. Why are you considering to do the front end? Do you notice issues?
On the Deauville I had head shaking issues around sharp bends, excessive diving during braking and especially with a load on the back.
Probably pre-empting things a little, as my Himalayan is still on the high seas atm. However, from experience, I know it is inevitable that I am going to hit at least one deep pothole/steep entry-exit causeway/wash away or miles after mile of endless corrugations that will cause the front end to bottom out, on most days that I ride. I suspect riding the Himalayan will be no different
Provided I can source the right spring rate and length, the rest of the process is pretty straight forward. The only technical issues are possibly having to machine up some collars to support the Gold Valves where they seat on top of the damping rod, drilling out the damping rod holes, machining the spacer tube to give the correct pre-load etc.
The whole process is documented in the Race Tech Motorcycle Suspension Bible. If you have the ability to do this yourself, you can make significant savings over buying a kit from Ohlins or the like.
I will gauge whether I want to go down this path after I have done a few multi-day rides, but am mindful of the fact that any improvement to the front suspension will only serve to highlight any deficiencies in the rear shock...Now that is a completely different animal to fix...(read expensive!!!).