I am also on 2.90. I can't work out why the default2 option isn't showing for me though.
Code:
C:\Program Files (x86)\get_iplayer>get_iplayer --modes=best --pid b04pvhmr --inf
o
get_iplayer v2.90, Copyright (C) 2008-2010 Phil Lewis
  This program comes with ABSOLUTELY NO WARRANTY; for details use --warranty.
  This is free software, and you are welcome to redistribute it under certain
  conditions; use --conditions for details.
INFO Trying to stream pid using type tv
INFO: pid found in cache
Matches:
2079:   Top of the Pops - 15/11/1979, BBC One, Classic Pop & Rock,Music, default
INFO: File name prefix = Top_of_the_Pops - 15_11_1979 b04pvhmr default
available:      Unknown
categories:     Music,Classic Pop & Rock
category:       Music
channel:        BBC One
desc:           David Jensen presents another edition of the weekly pop chart wi
th performances by the Jam, Cliff Richard, the Moody Blues, Kool and the Gang, S
ecret Affair, Ramblers, Showaddywaddy and Dr Hook and dance sequences by Legs &
Co.
descmedium:     David Jensen presents another edition of the weekly pop chart wi
th performances by the Jam, Cliff Richard, the Moody Blues, Kool and the Gang, S
ecret Affair, Ramblers, Showaddywaddy and Dr Hook and dance sequences by Legs &
Co.
descshort:      David Jensen presents performances by the Jam, Cliff Richard, th
e Moody Blues, Kool & the Gang, Secret Affair, Ramblers, Showaddywaddy and D
r Hook and dance sequences by Legs & Co.
dir:            I:\fri
dldate:         2014-11-28
dltime:         18:33:09
duration:       2400
durations:      default: 2400
episode:        15/11/1979
episodenum:     1
episodeshort:   15/11/1979
expiry:         2014-12-23T01:30:00Z
expiryrel:      in 24 days 6 hours
ext:            EXT
filename:       I:\fri\Top_of_the_Pops - 15_11_1979 b04pvhmr default.EXT
filepart:       I:\fri\Top_of_the_Pops - 15_11_1979 b04pvhmr default.partial.EXT
fileprefix:     Top_of_the_Pops - 15_11_1979 b04pvhmr default
firstbcast:     default: 2014-11-21T01:00:00Z
firstbcastdate: default: 2014-11-21
firstbcastrel:  default: 7 days 17 hours ago
index:          2079
lastbcast:      default: 2014-11-23T00:45:00Z
lastbcastdate:  default: 2014-11-23
lastbcastrel:   default: 5 days 17 hours ago
longname:       Top of the Pops
modes:          default: flashhigh1,flashhigh2,flashlow1,flashlow2,flashstd1,fla
shstd2,flashvhigh1,flashvhigh2,rtsphigh1,rtsphigh2,rtsplow1,rtsplow2,rtspstd1,rt
spstd2,rtspvhigh1,rtspvhigh2,subtitles1
modesizes:      default: flashhigh1=233MB,flashhigh2=233MB,flashlow1=116MB,flash
low2=116MB,flashstd1=141MB,flashstd2=141MB,flashvhigh1=439MB,flashvhigh2=439MB,r
tsphigh1=233MB,rtsphigh2=233MB,rtsplow1=116MB,rtsplow2=116MB,rtspstd1=141MB,rtsp
std2=141MB,rtspvhigh1=439MB,rtspvhigh2=439MB
name:           Top of the Pops
nameshort:      Top of the Pops
pid:            b04pvhmr
player:         http://www.bbc.co.uk/iplayer/episode/b04pvhmr/
senum:          s01e01
seriesnum:      1
thumbfile:      I:\fri\Top_of_the_Pops - 15_11_1979 b04pvhmr default.jpg
thumbnail:      http://ichef.bbci.co.uk/programmeimages/p02bkzzk/b04pvhmr_640_36
0.jpg
timeadded:      6 days 23 hours ago (1416595085)
title:          Top of the Pops: 15/11/1979
type:           tv
verpids:        default: b04q02dn
version:        default
versions:       default
web:            http://www.bbc.co.uk/programmes/b04pvhmr
INFO: 1 Matching Programmes
C:\Program Files (x86)\get_iplayer>
 
Is the plan with the changes you have now made that get_iplayer will always download the longer version of a programme unless told otherwise?