Hi Alberto.
Sorry for late reply.
The "shch" and "w" can be used at the same time to produce "щ" without collision.
In my opinion combination "TS" must be used for producing "тс". The reason is: а lot of russian words are using "-тс-", example: "прийдёТСя". If "TS" produce "Ц", that will be problem to write down such words. For letter "Ц" will be enough to use symbol "C".
Hope this will help!
Hi Alberto.
Sorry for late reply.
The "shch" and "w" can be used at the same time to produce "щ" without collision.
In my opinion combination "TS" must be used for producing "тс". The reason is: а lot of russian words are using "-тс-", example: "прийдёТСя". If "TS" produce "Ц", that will be problem to write down such words. For letter "Ц" will be enough to use symbol "C".
Hope this will help!