>>1874416X rating refers to line diameter, i largely ignore it because i tie my own leaders out of regular line and tippet is a scam. Ot goes from 0x-8x, you'll never realistically be in a situation where you need finer than 6x, i dont care how small your trico is. The number next to the # indocates hook size, #12 is a size 12 hook, #4 is a size 4 hook. As for line size matching fly size, dont worry about it too much. On your 5 weight for general fuckery I'd use 3x or 4x tippet, that will turn over most flies but be fine enough for smaller panfish flies.
>>1874462After 0x it goes in to 00x 000x etc
>>1874542Trailer for sure. Full rigid mountain bike will probably be best, good energy transfer on pedal strokes with wider tires for if the trail gets soft.