The View From Here ..
One of the best features of the Z Tron IR system is that it comes as a kit which makes it much cheaper. There are only a few parts so, with a bit of patience and practice you can DIY. There is a tremendous buzz to be had from successfully building your own Rx too !
The main thing is not to rush, relax, allow plenty of time to do the job. We don’t use circuit boards or plug connectors as these items weight half as much as the Rx.

For soldering very fine copper wire and surface mount components it is vital to use a fine soldering iron tip and small soldering iron.  Using low temperature small diameter solder makes the job much easier as well.

It is very important to be comfortable when soldering small parts. Clear your work table and use a heavy  podium made from a small pot full of coins. Hold the items to be soldered onto the pot with a blob of BlueTak. Have a low power desk lamp to provide good light. Move the pot around to get comfortable for each joint you solder -don’t struggle and get hot and bothered !!! Otherwise failure wins and you loose. Watch out the BlueTak does not stick to the hot parts.

When soldering enamel coated copper wire, the enamel should melt. This makes a horrible black mess. Also the enamel only melts at high temperatures. I scrape off a little of the enamel with a new scalpel before tinning the wire. I use a damp kitchen cloth to clean the soldering iron tip. Avoid breathing the solder fumes and don't accidently eat the stuff by soldering at the kitchen table!

Some folds gently clamp components before soldering using a simple beam clamp. I find it gets in the way and its not much use if you don’t have a circuit board

Replace your multi meter leads with much smaller size flexible wire and crocodile clips. I use brass tubes to plug into the multi meter. - CAUTION! DO NOT USE THESE WIRES FOR HIGH VOLTAGES OR CURRENTS - only for less than 300mA and 5 volts, electronics use.
 

Notes for making a TMREM twin steer Rx.
Don’t tin the circuit board ! Scrape off any paint that might be on the part of the board you are going to solder onto. Start by fixing the top MOSFET transistor, then do the resistor next to it, then the next transistor then the next resistor - otherwise there is not much room. I check that the pins are fixed to the board properly by holding two pins in the crocodile clips of the multi meter wires. Touch one pin onto the circuit board and the other to the pin of the part you are solder - not to the solder. If the joint is good you will get a buzz from your continuity checker.
I do one transistor, and then take a break. One evening should be set aside for doing the two transistors and the two small resistors next to them. The rest of the Rx is much easier.

I use the following items:

Soldering iron is an ANTEX XS25
with a tip that goes to a point for fine work and a normal tip for battry leads and other huge wires!
Solder is low temp. small diameter