hello , [ i don't know if it's the right place to post , so feel free to move it if necessary ]

Spring time is coming so , i managed to get some racks (Startech - RK120D) ;
- one of them is already full with all my c3750 switches.
- but i still have to install a Cisco 891w and some juniper SRX210h in the 2nd rack.
- some others routers/switches (Ubiquity , tp-link ,..) inside a third one.
so first, i am looking for a "cheap solution(s)" to install the c891w and SRX210 side by side on a 19 pouces rack.
that's raise others questions :do you buy special equipment(s) ,do you build them ,how do you deal with equipment that don't fit the rack standard ?
thank you for yours responses