I would shoot the pistol before deciding on new grips, especially wood grip panels. The Beretta is a big pistol with a chunky grip. Depending on your hand size you may or may not have difficulty reaching the trigger comfortably in double action mode while maintaining a grip where the pistol is optimally aligned with your shooting forearm. Wood grip panels are significantly thicker than the polymer panels and can make this worse. I personally like the G10 VZ grip panels or the ultra-thin G10 grip panels sold by Wilson Combat.
There is no reason to worry about the hammer dropping when you decock the pistol. Take a look at the pistol and rotate the lever into the safe position with the hammer held back. You will see that there is a pin that protrudes through the safety lever cylinder. That is the firing pin plunger. The hammer strikes that plunger and the plunger strikes the firing pin itself. The safety lever rotates that firing pin plunger out of alignment with the hammer and firing pin well before the hammer is released so it can not possibly strike the firing pin. The firing pin block safety also prevents movement of the firing pin due to inertial impulses.
Some people prefer converting the decocker/safety mechanism to a decocker only as on the G models of the 92FS. In this mode the lever decocks the pistol but then springs back up so there is no actual external safety. This eliminates the concern that some owners had of accidentally putting the pistol on safe when sling shotting the slide with an overhand grip. This used to be hard to do, but Beretta now sells a G conversion kit for the M9A3 that works on the M9/92 FS. I myself being a right-handed shooter prefer the Wilson Combat low profile safety lever. This eliminates the lever on the right side of the pistol, and greatly reduces the profile of the lever on the left side. The lever still functions as a safety/decocker but is virtually impossible to accidentally deploy when racking the slide. The lever is harder to use to take the pistol off safe, so if self defense use is a concern, I would use this lever primarily as a decocker, or if carrying the pistol, I would take it off safety after holstering. This lever eliminates the rather sharp and bulky external levers of the stock safety and makes rapid slide manipulation a lot more pleasant.
I do have a Wilson Combat oversized magazine release lever and a reduced force mainspring. You can very easily reduce the strength of the mainspring on the M9/92 FS with a spring swap. It is quite safe to go down to a 16# mainspring which is what the spring in the D model (double action only) Beretta 92D comes with. Some will go lighter still Wilson Combat sells springs as light as 12 lbs and Wolff Gunsprings also sells reduced force mainsprings and packs with several different strength springs that allow you to experiment. Lighter springs may come at the cost of reduced ignition reliability, however, so if self defense use is a consideration, I probably would not go lighter than 16 lbs. That will, however, make a big difference in the weight of your DA trigger pull, and some lightening of the SA pull as well.
By all means install a metal recoil spring guide rod if you wish. It will not make your gun shoot better nor improve reliability one iota. Some shooters claim an improvement in balance by adding more weight at the front of the pistol. All I can say is they must have sensitive hands to notice the difference. Disclaimer: I do have a steel guide rod in my pistol.
If the reach to the double action trigger is an issue for you, consider the Wilson Combat short reach trigger. This will get rid of the stock, polymer-coated steel trigger (not plastic trigger) and will reduce trigger reach a little. While the reduction in trigger reach with this trigger is pretty small, the combination of this trigger and the ultra-thin G10 grips will make a significant difference.
