but from the current structure, i think there wont have enough space for putting that soldering point on every space between numpad column and thats what xhjs (the designer) had told me
The discussion about soldering points was about relocating the numpad to the left side. I don't think that anyone who is now interested in cutting away
individual columns from the right side would be interested in reconnecting any of those.
For me at least, I am just interested in getting the smd components for the keys on the left of the cut out of the way so that I could make a clean cut and not have to reconnect anything. Instead of having so many to the right of switches, have them to the left, above and below.
Having milled grooves between columns would not be necessary, but would make things easier.
Having additional solder pads would be completely unnecessary.
Here is an illustration of what I mean. The PCB is seen from the bottom, so left <=> right from the description above. (click the picture to magnify)
BTW, I would use a 4" razor saw. Wear a dust mask and keep the vacuum cleaner held close all the time for safety.