Erased the first post.
Make it easy. IF modding is on your mind, buy the Maxi or a Disco, not the Varmint. The average airgunner is not going to want to mod the Varmint as factory spare parts are just not out there, much less after-market parts, so if you screw something up in the modding process, are going to have to make a new part yourself.
Happened this one turned out to be pretty efficient in air use, quite powerful for a .177, likes super-heavy pellets, and accurate. Changing it to something else (like slower/more shots per fill) can be done, but you're going to have to MAKE stuff rather than swap-stuff to do it.
With the Maxi/Disco, likely can just order parts (new or aftermarket) that could do what you intend doing.