Adding drop down guides ,,assistance,

[greystoneleatherllc]

LNKA Suspended Edge Guide #GB-6 bought a couple of these from amazon, quality seems good, will be installing on a Consew 227r and Singer 211-166 want to make sure I don't drill mounting holes in the wrong place. Also if any one knows of a mounting adapter/bracket to simplify the install and allow better positioning,   see attached pictures for where I think the holes will go thanks I intended to use 1/4" 20 thread screws any feed back about hole placement welcome just want to make sure I don't drill in the wrong spots ,,db

[Uwe]

The hole positions on the Singer 211 look reasonable, but I don’t have a 211 to verify. 

On the Consew 227, however,  your proposed hole on the right is directly in line with the presser bar - NOT a good spot! My 227 clone came with three tapped accessory holes as shown in the image below. Those are obviously good locations.