internal table looping problem

i have 5 internal table it_vbrk, it_vbrp, it_vbak,it_vbap, it_lips and it_kna1 ..( the select-options was likp-erdat and likp-vbeln)

based on that i have done select 'for all entries' on it_likp into it_likp have selected 3 flds from likp, 7 flds from lips. now using

for all entries on

it_lips i have selected 5 flds from vbrp into it_vbrp. based on for all entries on it_lips i have selected 5 flds from vbap.

now i have to populate my final internal table it_final.

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types: begin of it_final,  "this is my internal table flds arranged according to the list output
vbeln type vbap-vbeln,
posnr type  vbap-posnr,
erdat type vbak-erdat,
kunnr type likp-kunnr,
name1 type kna1-name1,
aufnr type vbak-aufnr,
matnr typr vbap-matnr,
arktx type vbap-arktx,
kwmeng type vbap-kwmeng,
vrkme type vbap-vrkme,
vbeln1 type lips-vbeln,
posnr 1type lips-posnr,
lfimg type lips-lfimg,
vrkme type lips-vrkme,
vbeln2 type vbrp-vbeln,
posnr2 type vbrp-posnr,
fklmg type vbrp-fklmg,
vrkme1 type vbrp-vrkme,
end of it_final.
now plz tell me how to populate this internal table? which is the right method :
(1)  looping at it_likp into wa_likp. "based on the likp-vbeln i am fetching the flds from lips.
     read table it_lips into wa_lips where vbeln =  wa_likp-vbeln.
      it_final-vbeln1 = wa_lips-vbeln.
it_final-posnr1 = wa_lips-posnr.
it_final-fklmg = wa_lips-fkimg.
it_final-vrkme1 = wa_lips-vrkme.
append it_final. endloop.
loop at it_final.
read table it_vbrp where vgbel = it_final-vbeln.
it_final-vbeln2 = wa_vbrp-vbeln.
...........
modify it_final index sy-tabix transporting vbeln2....
similarly fetch the records from vbap, lips etc.

(2 )another method.
loop at it_likp into wa_likp.
read table it_lips into wa_lips where vbeln = wa_likp-vbeln.
read table it_vbrp into wa_vbrp where vgbel = wa_likp-vbeln.
read table it_vbap into wa_vbap where vbeln = wa_lips-vgbel.
[ps: i am selecting vgbel and vgpos from lips and vbrp but not populating into it_final as it is not reqd.]
it_final-vbeln = wa_vbap-vbeln.
it_final-posnr = wa_vbap-posnr.
it_final-matnr = wa_vbap-matnr.
it_final-vbeln1 = wa_lips-vbeln.
it_final-posnr1 = wa_lips-posnr.
it_final-lfimg = wa_lips-lfimg.
it_final-vbeln2 = wa_vbrp-vbeln.
it_final-posnr3 = wa_vbrp-posnr.
it_final-fklmg = wa_vbrp-fklmg.
........
.........
append it_final.
clear it_final.
endloop.

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now plz suggest which one is a better method to follow and why? suggest me some tips to select which table to use loop first and how? where shud i use read table? plz site some codes as an example.

elaborate answers will be highly appreciated.