Here's the beginning of a list of Tower Sites and the approximate QL of the site. You're invited to reply with Tower Sites you've found. I'll try to edit them into my list here and we might come up with a full list one day.
Upper Stret East Bank
1664 2214 QL150
1940 1769 QL75
1709 790 QL75
958 370 QL75
1370 1624 QL165
Stret West Bank
1305 1301 QL30
779 1325 QL30
1952 2755 QL32
2321 2786 QL21
Holes In The Wall
385 298 QL18
769 471 QL36
Stret East Bank
1443 1723 QL100
1846 1305 QL105
1738 684 QL67
2007 1754 QL67
1740 490 QL150
741 277 QL150
965 910 QL100
Varmint Woods
1952 1750 QL75
1113 1505 QL75
3774 2500 QL30 - 45
3120 2030 QL25 - 50
4 Holes
1111 506 QL58
449 449 QL45
1519 1284 QL44
1726 1050 QL100
1815 1284 QL100
1677 1745 QL58
1596 2345 QL75
1308 2037 QL43
976 2047 QL50
Tir County
500 600 QL15
1483 455 QL10
2923 976 QL15
477 1356 QL10 - 15
Greater Tir County
594 1713 QL25 - 40
1052 1678 QL25 - 40
2340 1855 QL25 - 40
2848 1929 QL30 - 45
Lush Fields
2450 3046 QL25
1776 1810 QL24
1753 2425 QL50
1301 2463 QL50
791 3196 QL38
Mutant Domain
526 815 QL21
821 450 QL31
Clon****
970 4381 QL42
2016 2513 QL43
1518 2542 QL50
1255 1791 QL50
1380 1565 QL48
2032 652 QL75
2298 486 QL75
2562 1136 QL11