Peptides aren't going to help much for gaining size, they can have great nutrient partitioning effects making a recomp more effect or generally a bulk slightly more effective and make it easier to maintain muscle on a cut, but they're not really going to add a lot of size to you.
Better for things like maintaining gains or recomping.
Also, the longer you run them the better. Ipam you can run indefinitely but if you run something stronger like GHRP-2 it's recommended to run it for 2 months then take a break or switch to IPAM to offset some of the GHRH/prolactin sides etc.