This article is to exemplify the ideas. The comprehensive version might be added given to a technically viable chart making.
These are the 5 hiragana (HG) and katakana (KK) letters that are almost same;
HG (や か り に へ) = KK (ヤ カ リ ニ ヘ ).
So if you know one the other will be a hackjob.
But that won’t be too many. I am rearranging them into groups so it will be really easy for you to remember the alphabet in a few hours.
If your eyes are quite good at hiragana you will see some more of katakana quite easily.
(check this out; the top of hiragana is the katakana;
KI in き HG = KI キ in KK,
but like katakana bracketing hiragana can be bracketed for easy memory,
eg (KI き SA さ) in hiragana can be ambiguous so can be put at the same place for practice)
I had a plan for bracketing all such letters for hiragana long time ago but I haven’t done so. But not only hiragana-hiragana or katakana-katakana letter mismatching can happen in mind, also katakana-hiragana can throw you out of comfort
eg SE せ (HG) and SA サ (KK) … But usually self alphabet ambiguity is far frequent.
Idea; put them in one group and practice till you find a clue to see and remember the difference. I am onto making a good chart that highlights this useful trick.
Here are some examples;