check out the pictures of my mounts
1. speed o meter mount cat trike accessory 90 degree mount, i used the boom under the handle bar bottle cage screw mount no hole had to be drilled jst had to cut the mount down
2 avenir sattle bag seat mounted, i used some aluminum 1" thick by 1/8th" to wrap around the head rest bars. i used a small peice of wood to to prohibit it from collaping between the bars. the screws are on the inside of the head rest bars.
3. extended rear light mount Will be painted to match the bike. i used the 1' by 1/8th" stock to make the mount and drilled holes and mounted it under the bag mount. the aluminum is soft and was easy to bend.