You might find something like this useful. It plots line graphs of the sums at each interval, which might serve to help you select the best one for your purpose. The graph produced(*) using random data are pretty uninspiring, but serves its purpose.

Large; you'll need to scroll or scale

#! perl -slw
use strict;
use GD;
use List::Util qw[ sum ];

sub rgb2n { unpack 'N', pack 'CCCC', 0, @_ }

## Gen some data
my %counts;
++$counts{ int( rand( 5e3 ) + rand( 5e3 ) ) } for 1 .. 1e6;
my @keys = sort{ $a <=> $b } keys %counts;

my $gd = GD::Image->new( 10000, 2000, 1 );

for my $step ( reverse 1.. 10 ) {
    my $start = 0;
    my $last = 0;
    my $clr = 2**24 / $step;

    for( my $end = $start+$step-1; $end < $keys[ -1 ]; $end += $step )
+ {

        my $sum = sum( @counts{ grep( defined $counts{ $_ }, $start..$
+end ) } ) // 0;
#        printf "%4d - %4d : %d\n", $start, $end, $sum;

        $gd->line( $start, 2000-$last, $end, 2000-$sum, $clr ) if $las
+t;
        $start = $end + 1;
        $last = $sum;
    }
}

open IMG, '>:raw', 'junk14.png' or die $!;
print IMG $gd->png;
close IMG;

## Display the graph in the default image viewer
system 'junk14.png';
[download]