I would recommend you get a frame that will enable you to experiment with both band orientations, OTT and TTF, use light bands and small ammo to begin with until you have your grip and aiming style locked down. Just practice (safely) and experiment until you have your own personal shooting style. There’s plenty of videos on aiming techniques from catapult carnage and gamekeeper John on YouTube. You can move on to more expensive frames and heavier bands/ammo as your accuracy/technique develops.
Have fun, be safe, good luck.
Dan