Two proposals I have though:
You assigned both, q and Q to the greek capital letter 'theta', different in design, but they are both upper case 'thetas'. Then, you assigned 'j' to the lower case 'theta' and 'J' to the upper case 'phi'. Lower and upper case 'phi', however, are already assigned to 'f' respectively 'F'.
So, you could better assign the lower case 'theta' which is now assigned to 'j' to the letter 'q'. 'j' and 'J' are then no longer needed, so you might assign them e.g. to a 'spiritus lenis' and 'spiritus asper', which are used in Greek to indicate whether an 'H' before a vocale is pronounced or not (there is no 'eitch' (H) in the greek alphabet. The greek 'H'(eta) sounds like the english 'e`or german 'i').