FYI, as per Phil's recommendation....went to HD and purchased the following...
Cap screw, hex bolt & nuts...originally purchased a 7mm bolt, but was too big...also could not locate a full size nut as of yet!!!
now my grinding abilities are not the best....lol so what I did was used a file to smooth and "flatten" out the bottom of the screw for a full contact with the linkage. my grinding skills on the left....lol the file work in the middle and a screw as is on the right...as you can see with the screw in the middle the outer edge is removed for a totally flat surface. also did this with the hex bolt...
now you can have a choice as to what type of screw or bolt to use as to if you will ever need to do the min/air adjustment as per Dominic on the vehicle. the Cap screw uses a 4mm Allen hex wrench which I have is almost 4" L.
the Hex bolt uses a 8mm combo wrench which I have is almost 4 3/4" L for adjustments... (your sizes may vary)
each one will reach outside of the linkage area making adjustments on the vehicle easier. (although IMO and what Phil has shown, the Hex Bolt would seem the way to go)
for the original idle screw, I found that either a 2mm or 3mm Allen will fit that opening, but the keys are way too short to reach in and make any on car adjustments....