The 1818VSL is a better choice.
The first 2 inputs on the 44VSL are Mic/Instrument, while Inputs 3/4 are Mic/Line.
You need 4 Line inputs that have the game Gain Control Range and Input Impedance.
The 44VSL does not have what you need for your specific task of recording line outs of your 4 Track Reel to Reel.
Make sure to look at the specs: https://www.presonus.com/products/AudioBox-44VSL/tech-specs
- Line Inputs:
- Gain Control Range -20 dB to +20 dB
- Input Impedance 10 kΩ
- Instrument Inputs:
- Gain Control Range -30 dB to +50 dB
- Input Impedance 1 MΩ
The 1818VSL Line Inputs 3-8 (of which you'll use 4) will be adequate have the same specification that the 44VSL does, however it is across Inputs 3 - 8 and not just 3 and 4.
Line Inputs:
- Gain Control Range -20 dB to +20 dB
- Input Impedance 10 kΩ
The 1818VSL is a better choice for your needs in this case.