Careful consideration would need to be given to the political balance calculations if this were to be the case and agreed by all parties prior to the arrangement being confirmed.
Byddai angen ystyried yn ofalus y cyfrifiadau ynghylch cydbwysedd gwleidyddol os byddai hyn yn wir, a byddai gofyn i bob plaid gytuno arnynt cyn i'r trefniant gael ei gadarnhau.