I have been carrying folding knives and multitools in belt holsters since the 1970s. Being left handed, I always carried the holsters at my side (3 to 4 o’clock position), oriented in a vertical position.

This worked well when carrying items which weighed under 8 ounces, but trying to carry heavier tools was uncomfortable.

I replaced my normal consumer grade leather belts with stiffer, tactical type belts. That helped, but not enough.

What made a biggest difference was changing to a horizontal carry holster located next to my belt buckle. That placed the center of the holster at approximately the 10:30 position. I can now carry my heaviest multitool (10.3 ounce Leatherman SuperTool 300) in comfort and it does not interfere when sitting.

A few of my horizontal carry multitool sheaths are described in this thread:

http://edcforums.com/threads/horizontal-carry-holsters-for-multitools.42216/page-2#post-2120045