To forge slingbows with max tiers (3x10 tier levels) you would need 15000 boon points (3x5000). Le’st assume that we roll the best possible result in every forging round.
Example for absolute max points.
Protection paste 2(x6) = -100 vigour & 100 stability
Imperfect boon 2(x24) = -50 vigour & -100 stability & 2x400 boon points
Result = -1800 vigour & -1800 stability & 19200 boon points
Example where we also setup our boons (with quirks or defects).
Gums(x2x3) = -50 vigour
Corrupted boon 1(x3) = -50 vigour & -100 stability & 2x400 boon points
Vigour catalyst 1(x3) = (1+3)x30 vigour & -100 vigour
Protection paste 2(x4) = -100 vigour & 100 stability
Imperfect boon 2(x19) = -50 vigour & -100 stability & 2x400 boon points
Result = -1740 vigour & -1800 stability & 17600 boon points
Example where we also setup our boons (without quirks or defects)
Gums(x2x3) = -50 vigour
Corrupted boon 1(x3) = -50 vigour & -100 stability & 2x400 boon points
Vigour catalyst 1(x3) = (1+3)x30 vigour & -100 vigour
Pure boon 3(x14) = -100 vigour & -100 stability & 2x400 boon points
Result = -1790 vigour & -1700 stability & 13600 boon points
Now let’s look at more practical example with 50% gains (stability rolls average to 100+10x0,5, boon gains and losses average to 50%).
Gums(x2x3) = -50 vigour
Corrupted boon 1(x3) = -50 vigour & -105 stability & 2x400x0,50 boon points
Vigour catalyst 1(x3) = (1+3)x30 vigour & -100 vigour
Protection paste 2(x2) = -100 vigour & -105 stability & 4x52,5 stability
Pure boon 2(x8) = -50 vigour & -105 stability & 2x200x0,50 boon points
Pure boon 3(x8) = -100 vigour & -105 stability & 2x400x0,50 boon points
50% gains = -1790 vigour & -1785 stability & 6000 boon points
60% gains = -1790 vigour & -1768 stability & 7200 boon points
70% gains = -1790 vigour & -1751 stability & 8400 boon points
80% gains = -1790 vigour & -1734 stability & 9600 boon points
90% gains = -1790 vigour & -1717 stability & 10800 boon points
100% gains = -1790 vigour & -1700 stability & 12000 boon points
Slingbow with T6 tiers x 3 = min 4500 boon points
Slingbow with T7 tiers x 3 = min 6000 boon points
Slingbow with T8 tiers x 3 = min 9000 boon points
Slingbow with T9 tiers x 3 = min 12000 boon points
Slingbow with T10 tiers x 3 = min 15000 boon points
Hope this helps to give some kind of sense why we don’t see those perfect slingbows everywhere.