What to consider when Pairing a matress topper with a new mattress

I recently purchased a pure green 3" soft latex mattress topper. I’m in the market for a new mattress and most of the matresses i’m looking at have at least a 1" comfort layer. Would i be able to get a thinner mattress as a result of already having a 3" topper? Also, I’m predominately a side and stomach sleeper. Should i be looking for a thicker support layer? I’m just looking to make the best combination with my existing gear. Thanks for your help.