Enjoyed your vid, Mig21 is my favourite module in DCS. Couldnt stop chuckling as your voice reminds me of someone doing a Bing Crosby impression, I kept expecting a few shooby doobys etc lol
4:12 RPM1 is used to set the correct engine state, not 2. Hence the low pressure compressor's state is the reference for setting the appropriate thrust (manual p. 65).
Leatherneck did supply a sort of english cockpit though a good portion of it remains in Cyrillic, if you chose to use that texture than it's a simple matter of selecting English as a setting in the avionics language settings in the gameplay tab of the options menu. Another option is to use one of the many mods availble such as this one - www.digitalcombatsimulator.com/en/files/1712433/ . Have not ran that one myself though it appears up to date. Alternatively you could manually edit the textures from: DCS World OpenBeta\Mods\aircraft\MIG-21bis\Textures Should be a .zip archive in there containing the textures.
In that case I'd say you have two options, one would be to buy steam cards since they sell the MiG-21 on steam, or you could buy a visa/mastercard pre-paid card from a convenience store or something.