What are you looking for? A tobacco? A menthol? Coming from Marlboro reds (and before that Camel straights), I needed a strong tobacco flavor up front. Vapor4life's Kamel and Dunhall were decent for that, and in DIY I came up with a tob4 mix that is strong. As time passed I wanted a smoother tobacco, did tob5 (similar to BWB's Marlboro variant).
As to menthol, crystals do work, but I agree they can be a PITA to work with. The perfumers apprentice (TPA) also sells the menthol liquid variant, easier to work with, consistent.
Yes, skin absorption occurs, but if you're moderately careful this isn't like dealing with plutonium. Use pipettes and/or syringes if dealing with small quantities of nic base, graduated beakers for larger quantities, clean any spills promptly, use a paper towel to wipe off any nic base that gets on your skin (if you don't choose to go the glove route). I use a small tray with raised edges for mixing, keep all the working liquids on it, makes it simpler to contain things and clean.
Your sense of taste will absolutely change over time. What you like at first may seem like dreck later. You may also hit days where nothing seems to have much flavor (a strong menthol backup can be handy for those times); entirely normal. Concerning harshness, perhaps a slight sensitivity to PG, VG, or a particular flavoring, though it could just be normal new-to-vaping -- the draw on a pv isn't like a cig, and the need to drink lots of water can take a bit before it becomes a habit.
Good luck!