Using different Magnesium supplements with Vit D therapy for deficiency

I have a Vit D level of 7.6 and have been started on a high dose to increase it, 20,000iu 3 x a week of Colecalciferol. I was taking Magnesium Malate, sporadically, but it upsets my stomach (I will try the recommendation here to see if I can improve that issue). I have just started using a Mag Oil Spray, also occasionally take an Epson Salt bath and the days I don’t take the Vit D mega dose I would like to take a multi vit, just to cover all bases.

I know I am deficient as my Dr hadn’t told me about needing Mag before I started the treatment and I have since experienced awful leg pain for which I sprayed the oil on...it stung but then calmed the pain. My questions are: is it ok to take different Mags in one day and am I taking too much via different methods? Given my depleted Vit D level I have no idea how much would be ok.