Over the near twenty years I've owned my 1997 900 I've played with the suspension and geometry quite a lot- especially as when I bought it at two years old I was riding a 1996 GSX-R750WT which was probably one of the best handling bikes of the time.
So like you, I felt the Monster very slow steering, in fact it under-steered horribly always wanting to push wide on corners unless being driven round quite hard but then, again as you're experiencing it kicked off bumps making for a very 'exciting' ride down the country lanes I favoured.
First to go were the Dunlop tyres in favour of some Pirelli Dragons (we are talking some years ago still), this was better but better still was raising the back up and getting five lines showing on the forks after pulling them through the Yokes.
Around this time I also bought and fitted a Nitron rear shock and felt I was getting somewhere so then it was onto messing with fork oil weights and air gaps- my bike was fitted with Marzocchi forks where one leg controlled the Compression and the other Rebound damping- when I say 'controlled' I use the word loosely as by any reckoning it is asking a lot for individual forks to work well like that.
This went on for a while, all the time using Pirelli tyres (up to Drangon Evos) which seem to suit the early bikes well before finally biting the bullet on the Monster after using Maxton to sort out the forks (and rear shocks) on my 1965 Ducati race bike which transformed it and so had a similar effect on my Monster making me wish I had done it years earlier and not bothered fecking around with them.
As standard the (Marzocchi- can't speak for Showa) forks feel very notchy and harsh and kick off small bumps, this is because they have too much compression damping over small movements, however when you brake very hard you may be able to feel the forks bottom out, this is because there is not enough support in the compression damping over large movements.
The other problem with the damping is there is not enough rebound damping which means when you let go of the brake the forks spring back at you and the bike does not turn into the corner as well as it should, this also causes the bike to run wide out of a corner. The springs inside the forks are actually too hard and Maxton fit softer springs to suit your rider weight and also to suit what type of riding you do.
The biggest improvement felt is from increasing the rebound damping to control the forks extension, reducing the compression damping over small bumps to stop the forks kicking off small bumps and increasing it over large movements giving more support with the spring.
So my final set up is- Maxton GP20 cartridges in the forks with them pulled through the Yokes so four lines show (I would have it so five show but had fitted slight flatter bars to put a little more weight over the front so they prevent them coming through anymore).
Rear shock is still my Nitron (amazing customer service and quality) with the rear joints screwed out 40mm from the bottom of the 'Hoop' to the eye centre.
Point to note on that is originally I had them 30mm out but fitted Michelin Pilot Road 3's which slowed the steering down (enough to make me think the front was down on pressure when I first rode it) and wound them out another 10mm to compensate.
Lastly, if you go the Lougi Moto extenders- which are beautifully made and great quality but according to Rich, the latest incarnation of them means you will need to chop some of the thread off the Rose joints as they won't screw in flush as is.
Obviously these are just my thoughts but I hope some is of use
