I made/use an imo1.1a inside an a4tech.
Hole probably needs adjustment (guessing).

But I can guarantee mod includes:
Cutting
Scraping
Sawing
Fitting
Glueing


Recommended Tools:

Sharp blade or two (scalpel or immovable blade is easiest)
SuperFine fretsaw blades (is good to have)+lockable forceps or some small tong to hold it.
Hacksaw blade for:
Extra Plastic material (old slot cover is a good source, or buy a plastic sheet at a hobby store)
Super-GEL (gel-glue enables fitting before firm pressing, and also easy to apply).
Tweezers
Toothpicks (glue handler and allround poking tool)
Fine sandpapper+(4surface)nailPolishingstick (if you want to fiddle or design pretty buttons)
Kitchen paper


Tip... Dryfit, test and think... best done before.
Also try to measure/figure out sensor height to get it equal. TEST RUN it in the new casing before it's assembled (tape can be useful). Hopefully not much need to be done, also a SMALL variance IS tolerable.

GL if you try!