I personally would go for the cheapest seats for Evan and Les Liaisons. The Music Box and, particularly, the Booth are small theaters and you really won't miss sitting in the orchestra.
I am currently on a semi-annual show watching trip. I purchased the following tickets, based on the following logic:
-- Hamilton -- Orchestra (non-premium). I bought the tix a year ago and was able to get Row Q and R on the center aisle. No brainer...it was never going to be at TKTS, the balcony is pretty far away and not much cheaper than the $177 I paid for my seats.
-- The Humans -- $39 rear mezzanine. Reason: the seats three rows in front of me were $142...seemed like a no-brainer. J1-3-5. Also, when I bought them, I did not realize it would be at TKTS. The seats were perfectly good and I loved the performance. (Also, since at least 1/3 of the action took place on the second level, I suspect that I was no further from the action than the $142 rear orchestra seats). Note: $39 was still $30 less than TKTS orchestra prices.
-- The Front Page -- Bought Orchestra because its Nathan Lane and amazing cast, and I was able to get third row on the center aisle for $142.
-- The Color Purple -- TKTS. Only spent $66 for rear orchestra center, 4 rows from the back. Not need to buy in advance, to pay full price, etc.
My point is that I will sometimes pay top price, sometimes do TKTS which mostly gets you orchestra, and sometimes get the cheapest tickets...generally when the theatre is small. The Booth and the Music Box definitely fit the bill.