diff --git a/src/libslic3r/GCode.cpp b/src/libslic3r/GCode.cpp
index 2c28e4841f..a9336b5f4f 100644
--- a/src/libslic3r/GCode.cpp
+++ b/src/libslic3r/GCode.cpp
@@ -2463,9 +2463,11 @@ void GCode::_do_export(Print& print, GCodeOutputStream &file, ThumbnailsGenerato
 
         CalibPressureAdvanceLine pa_test(this);
 
-        auto fast_speed = CalibPressureAdvance::find_optimal_PA_speed(print.full_print_config(), pa_test.line_width(), 0.2);
-        auto slow_speed = std::max(20.0, fast_speed / 10.0);
-        
+        auto fast_speed = CalibPressureAdvance::find_optimal_PA_speed(print.full_print_config(), pa_test.line_width(), pa_test.height_layer());
+        auto slow_speed = std::max(10.0, fast_speed / 10.0);
+        if (fast_speed < slow_speed + 5)
+            fast_speed = slow_speed + 5;
+
         pa_test.set_speed(fast_speed, slow_speed);
         pa_test.draw_numbers() = print.calib_params().print_numbers;
         gcode += pa_test.generate_test(params.start, params.step, std::llround(std::ceil((params.end - params.start) / params.step)) + 1);
diff --git a/src/libslic3r/calib.cpp b/src/libslic3r/calib.cpp
index 162d7b9b5a..224479c097 100644
--- a/src/libslic3r/calib.cpp
+++ b/src/libslic3r/calib.cpp
@@ -424,6 +424,13 @@ std::string CalibPressureAdvance::draw_box(GCodeWriter &writer, double min_x, do
 
     return gcode.str();
 }
+CalibPressureAdvanceLine::CalibPressureAdvanceLine(GCode* gcodegen)
+    : CalibPressureAdvance(gcodegen->config()), mp_gcodegen(gcodegen), m_nozzle_diameter(gcodegen->config().nozzle_diameter.get_at(0))
+{
+    m_line_width        = m_nozzle_diameter < 0.51 ? m_nozzle_diameter * 1.5 : m_nozzle_diameter * 1.05;
+    m_height_layer      = gcodegen->config().initial_layer_print_height;
+    m_number_line_width = m_thin_line_width = m_nozzle_diameter;
+};
 
 std::string CalibPressureAdvanceLine::generate_test(double start_pa /*= 0*/, double step_pa /*= 0.002*/, int count /*= 10*/)
 {
@@ -496,14 +503,15 @@ std::string CalibPressureAdvanceLine::print_pa_lines(double start_x, double star
         // gcode << move_to(Vec2d(start_x + m_length_short + m_length_long, y_pos + (num - 1) * m_space_y + 7), writer);
         // gcode << writer.extrude_to_xy(Vec2d(start_x + m_length_short + m_length_long, y_pos + (num - 1) * m_space_y + 2), thin_e_per_mm * 7);
 
-        DrawBoxOptArgs default_box_opt_args(2, m_height_layer, 0.6, fast);
+        const auto     box_start_x = start_x + m_length_short + m_length_long + m_length_short;
+        DrawBoxOptArgs default_box_opt_args(2, m_height_layer, m_line_width, fast);
         default_box_opt_args.is_filled = true;
-        gcode << draw_box(writer, start_x + m_length_short + m_length_long + m_length_short, start_y - m_space_y, number_spacing() * 8,
-                          (num + 1) * m_space_y, default_box_opt_args);
+        gcode << draw_box(writer, box_start_x, start_y - m_space_y,
+                          number_spacing() * 8, (num + 1) * m_space_y, default_box_opt_args);
         gcode << writer.travel_to_z(m_height_layer*2);
         for (int i = 0; i < num; i += 2) {
-            gcode << draw_number(start_x + m_length_short + m_length_long + m_length_short + 3, y_pos + i * m_space_y + m_space_y / 2,
-                                 start_pa + i * step_pa, m_draw_digit_mode, m_number_line_width, number_e_per_mm, 3600, writer);
+            gcode << draw_number(box_start_x + 3 + m_line_width, y_pos + i * m_space_y + m_space_y / 2, start_pa + i * step_pa, m_draw_digit_mode,
+                                 m_number_line_width, number_e_per_mm, 3600, writer);
         }
     }
     return gcode.str();
diff --git a/src/libslic3r/calib.hpp b/src/libslic3r/calib.hpp
index fdabd47cc1..ee74d98a63 100644
--- a/src/libslic3r/calib.hpp
+++ b/src/libslic3r/calib.hpp
@@ -187,7 +187,7 @@ protected:
 class CalibPressureAdvanceLine : public CalibPressureAdvance
 {
 public:
-    CalibPressureAdvanceLine(GCode *gcodegen) : CalibPressureAdvance(gcodegen->config()), mp_gcodegen(gcodegen),m_nozzle_diameter(gcodegen->config().nozzle_diameter.get_at(0)){};
+    CalibPressureAdvanceLine(GCode* gcodegen);
     ~CalibPressureAdvanceLine(){};
 
     std::string generate_test(double start_pa = 0, double step_pa = 0.002, int count = 50);
@@ -199,6 +199,7 @@ public:
     }
 
     const double &line_width() { return m_line_width; };
+    const double &height_layer() { return m_height_layer; };
     bool          is_delta() const;
     bool         &draw_numbers() { return m_draw_numbers; }
 
@@ -212,10 +213,10 @@ private:
     double m_nozzle_diameter;
     double m_slow_speed, m_fast_speed;
 
-    const double m_height_layer{0.2};
-    const double m_line_width{0.6};
-    const double m_thin_line_width{0.44};
-    const double m_number_line_width{0.48};
+    double m_height_layer{0.2};
+    double m_line_width{0.6};
+    double m_thin_line_width{0.44};
+    double m_number_line_width{0.48};
     const double m_space_y{3.5};
 
     double m_length_short{20.0}, m_length_long{40.0};