I came up with an alternative to the 2 card shadow system. In essence, you reuse a 3 digit major system, learn how to associate 16 suit cards, which will allow you to create pairs of 1040 cards as opposed to 1352 in the original shadow system. The rest of the cards consist of face cards ( kings, queens and jacks ) which have quite complicated rules in the original 1352 card shadow system and lots of new numbers you would have to memorise so for those cards i just use my 1 card system images.
The shadow system works by having pairs of suit associations, where each number has two variants - an ordinary pair and a shadow pair. The ordinary pairs stack on each other. Lets say i draw 4 ordinary pairs in a row, all i do is add 4 images to one locus. If i come across a shadow pair, i place it as the last image in the locus and move on to the next locus - in essence the last card of each locus is a shadow image.
With my variation of the 2 card system, every time i draw a king, jack or queen i use a single image and place it in a locus, without shadow rules. Due to the low volume of such face cards ( 12 in total ), its extremely easy to not confuse shadow and ordinary cards with face cards.
if you draw a number card with a face card ( queens, kings or jacks ), then the three digit number begins in the following way: jacks - 400s, queens - 800s, and kings omits the first numbers so you can reuse a 2 digit system. So the first number becomes the face card ( or no face card in the kings variation ), the second number is the suit combination and the third number is the number of the first card ( A, 2 - 10 ). Lets say i draw the 2 of spades and queen of hearts: the first number is 8 which corresponds to queens, the second number is the suit pair, which is in this case 1: 
, and the last number is 2 so we get 812
If a deck ends with a number card, use a 1 card system fallback
Cards starting with a red suit are shadow cards and cards starting with black are ordinary and stack on each other
Suit associations:
( second pair starting with a red suit is a shadow pair)
0: /
1: /
2: 
/ 
3: /
5: /
6: /
7: /
9: /
The 3 digit images are put together as such: The 1st number is the suit pair, the second and third are the number cards numbers.
- The ace functions as a 1 if placed in the second or third position
- 10 functions as a 0 if placed in the second or third position
Example
Lets say i draw the 2 of hearts and 8 of spades. First i look up the suit pair, see that it corresponds to { 1/A: / }, so the first number is 1, then i look at the numbers of the cards in order, which are 2 and 8, which means that then final number is 128 which is “hot knife” in my 3 digit major system. I move on to the next locus because this was a shadow pair, and then draw a king of hearts for which i have a preset image of 001, and place the card as usual without any extra rules.
Does anyone have any recomendations or improvements to make