There are 8 pairs of magnets reacting with each other in every turn in a 2x2, while there are only 3 pairs of magnets reacting with each other in every turn in a skewb. Also, skewb needs stronger magnets to be held in cube shape.
My recommendation is to use 4*2 magnets as base magnets on your skewb, and utilise the extra magnets from your ylm 2x2 to adjust the magnets strength of your skewb by stacking the ylm magnets on top of the 4*2 base magnets (as 4*2 magnets may not even be strong enough for a skewb). 3*2 & 3*1.5 magnets are very useful when you want to fine tune the magnets strength.