depends on the challenger and stats of your pet, i used no shield...but my pet was way stronger than anything released voidberry potions, prickly potions every plot has its own niche, tnt releases challengers that have some strength or weakness, causing some items to be very effective and inflate rapidly
Do you want to do good in the plot for plot points to get items to sell? You'll probably be spending money to get high up enough to do well. Alternatively you could invest in a lab ray to get a lab rat. I didn't need shields as like Rise my pet was strong enough (aside from Oblivion) to beat the others and max with ease (League 13 though, you could easily get away with the lower league pets). In terms of icons, sword of skardsen is really cheap now. 1p battles usually ignore icons, therefore it's the number of icons that counts as opposed to icon type. It is hard to say what future opponents there'll be, so the best bet is just to have a strong pet. Or have a friend that you can borrow pets/weapons from to max them out. At the end of the day the point totals will be really similar.