I'll make an instruction of how to make customised push rods for your micro helis. There are many reasons why you would need such a customised push rods.
For me it was the customised head for my K130 helis which I use the Tarot450 tail assembly.
The reason I chose the Tarot tail assembly, the grips have builtin thrust bearings, hence totally eliminate the centrefugal loading on the grip's radial bearings.
Let me know if you are interest in this head from the Tarot 450 tail, I'll make some instructions.
Now... the instruction for making push rods.

Tools and parts

paper clips giant (1mm) or large (0.8mm)
2 sets of drill bits: 0.7mm for small rods and 0.8mm for large rods.
a portable hand drill.
a pair of long nose pliers
a pair of side cutters

mini tap and die set (tools used in making jewellery )
delux : https://www.ebay.com.au/itm/Mini-Tap...s/360976520001
or
economy (not sure if it can do the small rods as I don't have this tool) :
https://www.ebay.com.au/itm/8-PCS-MI...G/273136351686

I have used 2 types of paper clips (yup, the humble metal paper clips) one is giant (1mm in diameter) and large (0.8mm in diameter).
Why I use them? three reasons: cheap, easy to make threads and can be bent in serious crashes that may save servos.

The giant clips are being used on the hcp100s, K120 and K130 size. The large clips are being used in smaller helis like hcp60, k110.

For this instruction, I'll use the hisky hcp60 push rods which are in 0.5mm in diameter.

Start to make thread on the paper clip (which ever size that fits your servo)

For this example, I made a thread of about 10mm long, There is no harm if you make it longer.

Use the appropriate drill bit to enlarge the hole of the plastic linkage. Mark on the drill bit the max length the push rod will go into the plastic link

You can either use the tap tool or use the threaded push rod to tap the plastic linkage. I used the rod as it was very easy to tap the linkage with the rod.

Fit the linkage onto the push rod and ensure it is all the way in (ie: the shortest length this push rod can be).

Now straighten out the metal paper clip and prepare to trim it down to length.

Hint: if you found the drill bit is too small to fit in the 'chuck' of the hand drill tool, here is a hint.
get a small enamel wire (0.3mm is best), wrap around the drill bit before insert it into the chuck.
You can see in the photo and that what I did for my drill bit.

Measure the push rod to your desired length.

In my case, the plastic linkage length is 5mm. For strong linkage, I have reserved 2mm of threads.
So my minimum push rod length is 20mm and maximum is around 23mm .

Start to bend the end of the rod at 90 degree then using the long nose pliers (with a gap of 1.5mm, bend it the rod to form a U shape.

Now cut the end of the push rod leaving an ample length of about 3mm.

Check your new push rod on your servo (you may have to enlarge the hole on the servo arm).

Now you can trim the end of push rod down to the correct length .