I have an idea how to set up a "Two knights handicap" game online.
This kind of game is played between two players, one is stronger than the other, the stronger player play without two knights to make the game competitive..

For this to be possible, you and your opponent have to make the following moves:
the stonger player as Black and the other as Red who move first...
1) Cxb1 Cc8
2) Cb3 Cb8
3) Cxh10 Cg8
4) Ch5 Ch8
5) Ch3 .......
Now is the Black's move and the so called "two knights handicaps" game is set up

There is the "Iron center pawn" rule, it provide some protection for the center pawn because of lack of protection from missing two knights.

the center pawn only can be captured with a direct check, for example, Cxe7+ or Rxe7+

It is a idea to train the weak player how to defend with material advantages...especially for the beginner....